Transcriber’s Note:

The cover image was created by the transcriber and is placed in the public domain.

The Manufacture of Tomato Products
INCLUDING Whole Tomato Pulp or Puree, Tomato Catsup, Chili Sauce, Tomato Soup, Trimming Pulp

BY

W. G. HIER

Technologist in the Canning and Preserving of Tomato Products

Formerly Chief Chemist and District Factory Supervisor of The T. A. Suider Preserve Co. of Chicago

Published by

W. G. HIER

2324 South Columbine Street

Denver, Colorado

COPYRIGHT 1919

BY

W. G HIER

DENVER

THE BROCK-HAFFNER PRESS CO., PRINTERS

1919

Preface

The past ten years have seen revolutionary changes made in the tomato product manufacturing business. Old methods of making tomato pulp, catsup, chili sauce, etc. have been discarded, and the modern plant presents a very striking contrast to the plant of former days.

In this book I have tried to present all the methods used which have merit, and to bring forth the advantages and disadvantages of each so that the packer can weigh them and decide which is best to use under the conditions which obtain at his plant. In some cases one method is universally applicable and has advantages which stamp it as superior, but more often varying conditions of manufacture in different localities make it impossible to recommend any one method for everyone.

In writing the text I have had to rely almost entirely on the experience gained during the seven years in which I have been engaged in the manufacture of these products, as there are no books on the subject, and no sources of reference except the bulletins prepared by Mr. B. J. Howard and Mr. C. H. Stephenson of the Bureau of Chemistry, U. S. Department of Agriculture, on the sorting and washing of tomatoes, the handling of tomato trimmings, and the effect of proper and improper sorting and washing on the content of micro-organisms as determined by microscopical examination.

I wish to thank Mr. B. J. Howard of the Bureau of Chemistry for the valuable suggestions and information he gave me with reference to portions of the text of Chapter II and Chapter VII, and also to thank the Bureau of Chemistry for permission to use many of their photomicrographs and photographs.

W. G. HIER.

April 22, 1919.

PART I
The Manufacture of Whole Tomato Pulp or Puree

Table of Contents

CHAPTER I
OBTAINING GOOD TOMATO STOCK

Value of Good Tomato Stock

Obtaining a good quality of tomatoes at a price which is not prohibitive is a problem which in many localities is becoming more difficult to canners and catsup makers each year. Every experienced manufacturer knows that regardless of the expertness with which he may work up his tomatoes into the finished product, he cannot expect to get good quality unless he has good stock to begin with. It is true that by using intelligence and extreme care in the manufacturing processes one manufacturer will make better pulp or catsup from tomatoes of fair quality than another man can get from the best quality of stock. This same care and intelligence applied, however, in working up high quality tomatoes will probably show a greater difference in the finished products than was apparent in the tomatoes from which these products were made; in other words, the goodness of good tomatoes becomes accentuated by the manufacturing process.

In order to insure as large a proportion as possible of good quality stock, as well as a good yield per acre in tonnage, manufacturers are each year realizing the necessity of closer co-operation with the farmer. Where in growing tomatoes under contract it was formerly largely up to the farmer to buy his seed and raise his plants and set them out, it is now the usual custom to supply the farmer with seed of the desired variety and of high germination test, and in many cases to go a step farther and supply him with plants six to eight inches high, ready for setting out in the field. Unquestionably, the best results are secured by growing the plants for the farmer. The average farmer does not go about the raising of his plants in an intelligent way, and he will not devote the time to the plant-raising business that it should have.

Plant Raising

Most packers are agreed that the best plant is raised by starting the seeds in rows in hot beds, transplanting to cold frames when they are two to four inches high to harden them and make them stocky, and again transplanting to the field when the plants are six to eight inches high. This method produces a dark green, bushy, thick-stemmed plant of high vitality, which is so essential to a good yield. What a contrast to the average plant raised by the farmer—the seed often broadcasted, either in a hot bed or in a spot in the garden where the soil has not been specially prepared for plant raising, and when the plants, a large number of which are thin, pale green, and spindly looking, attain a height of anywhere from six inches to a foot they are all set out in the field and allowed to struggle along as best they can. When one looks at the kind of plants that are so often set out he can see at least one reason why yields of from three to seven tons per acre are so often obtained from ground which should yield twice that much, and why the plants are easy victims to blight and other diseases.

A prominent canner recently told me that by raising the plants for his farmers he had increased the average yield 4 tons per acre.

Use of Fertilizer

So many articles have been written on tomato culture for canning plants by experienced horticulturists that the subject will not be dealt with extensively here. In these articles emphasis is usually laid on the desirability of the use of commercial fertilizer, not only to increase the yield, but to hasten the maturing of the crop so that a large proportion of it can be harvested before frost.

My experience testifies to the wisdom of this in practically all cases, and with late maturing varieties such as the Stone tomato, in regions subject to early frost, and especially where planted on low ground, it is absolutely essential that fertilizer be used if a good percentage of the crop is to be harvested.

Methods in East and West

In the Tri-States—that is, Delaware, Maryland, and New Jersey—quite a different situation exists from that in the middle west or far west. The western packer has practically all of his tomatoes grown under contract, while the Tri-State packer, although he tries to contract as much acreage or tonnage as possible at a reasonable figure, is up against the competitive buying of the open market for a large proportion of his raw stock, as there are always a large number of farmers who are willing to gamble that the coming season will be a good one for playing the open market. In this case the buyer usually cannot be as particular about the quality of the tomatoes he buys as can the packer who has his tomatoes all grown under contract at a specified price, and who can exercise supervision over his farmers. This is particularly true in seasons of short crop, when the grower sells his tomatoes on the market and can afford to be very independent, and buyers are wildly forcing up the price by competitive bidding, and taking whatever they can get. Even if the eastern grower is under contract for his entire crop, if the crop is short, and high prices are prevailing on the market, it is the exceptional grower who will live up to his contract, and often to get an excuse for breaking his contract he will deliver very poor tomatoes right along in the hope that they will be objected to, thus giving him the liberty of disposing of them elsewhere.

The eastern packer, however, is blessed with a longer season in which to operate. While in the west there are seldom enough tomatoes to justify a run at the factory before August 15th, the Tri-States packer starts in on the early crop about the 25th of July, and his crop is not as liable to be severely injured by an early frost as is the western crop.

Canning and preserving plants in the west, being scattered rather sparsely over a very large territory, and being farther away from the large centers of population than in the east, the western packer is able to get a large percentage of his tomatoes hauled to the factory by wagon. This is indeed a big advantage, not only in the saving of freight and handling expense, but in the condition of the fruit when delivered to the factory. Probably having been picked not more than twenty-four hours before delivery, the wagon-hauled tomatoes are solid, and because the skin is not broken by repeated handling, thus preventing the growth of molds, they require very little sorting, in fact, no sorting at all in some cases. A load of tomatoes which requires no sorting at all, however, is unusual. If the packer can get his growers to use spring wagons for hauling tomatoes, it is a big advantage, especially if the fruit must be held any length of time at the factory. If the wagon-hauled tomatoes can be worked up quickly the packer gets 100 per cent value for them, which he very seldom does get on shipped tomatoes, which commonly undergo a loss of between 5 and 20 per cent in shipment, depending upon the time involved in shipment, the ripeness of the fruit, the amount of handling it received, the condition of the weather, the kind of crate in which the fruit is packed, and the amount of ventilation it received in transit.

Shipping Tomatoes

Shipment by water, although slow, has the advantage of smoothness of transit, and the crates or baskets of tomatoes are not subjected to the frequent joltings of rail shipments, and it is to be remembered that every jolt makes the tomatoes settle to a certain extent in the crates and mashes the tomatoes in the bottom layers. The best car for rail shipments is the slatted car or stock car, which permits of better circulation than any of the other types. A box car should never be used, as it allows the fruit to heat very badly, and there is no circulation of air. The crates in the slatted cars should be so stacked as to allow as much circulation of air through the car as possible. However, care must be taken that the crates are so stacked that they will not shift. A small air space can always be left at the end of every other row on each side without endangering the stability of the crates, and a large air space can be left at the top.

Tomato Crates

One advantage in the use of the basket over the crate in shipments is the advantage of better circulation of air through the piled baskets of fruit, due to the conical shape of the basket. Good ventilation is thus supplied without danger of the baskets shifting during shipment. The ⅝-bushel basket is used almost universally in the east, while in the west the crate holding a bushel is the common container. The construction of the crate is a more important item than is often thought. The most important point, of course, is strength in construction, and the use of a wood which will not warp easily by alternate soaking and drying out, allowing the nails to become loose and the bottoms to begin to fall out of the crates after a half season’s use. The slats of the crates should have rounded, smooth edges so as not to cut the surface of the tomatoes when they are jolted and weighted down during shipment. The slats should be only close enough together to hold the small tomatoes, so as to permit of as much air circulation as possible. This particularly applies to the bottom of the crates, which become soggy and musty after a little use, and the openings soon become clogged up with tomato substance. It is important to turn a steam hose over the bottoms of such crates to clean them out before returning to the point of shipment. If the empty crates pass along on a chain belt after dumping, this steaming can be accomplished easily. Accumulated decaying tomato substance in the bottom slats not only rots out the crates, but contaminates otherwise good tomatoes every time the crate is used. The crate should also be as shallow as will permit of easy handling, so as to distribute the weight of the tomatoes over as much surface as possible. A shallow, broad crate is preferable to a deep, narrow one.

Degrees of Ripeness for Shipping

The proper degree of ripeness for tomatoes to be shipped depends, of course, upon the length of time it will take for them to arrive at their destination. Dead-ripe tomatoes will stand very little handling and shipping, particularly if the weather is warm and damp, as it so frequently is during tomato season. It is important, too, not to have the tomatoes delivered to the shipping station too underripe, as they are very apt to rot before they become red enough to cook up into a product of good color. That the employee in charge of receiving tomatoes at the shipping point should be a man of experience and good judgment as well as tact in dealing with the farmers, is apparent. So much depends upon the control he exercises over the farmers in getting them to pick their fruit at the proper degree of ripeness. If he falters, is uncertain, and changes his mind a few times, he is lost, as the farmers soon lose confidence in his judgment.

It is always difficult to impress upon the farmer the fact that tomatoes gain in weight during the ripening process, and the riper they have their tomatoes the more they get in dollars when they drive up on the scales. This argument cannot be advanced when the tomatoes are bought by the basket, as they are in the east, but when paid for according to weight and not volume, the ripeness of his tomatoes is an important point for the farmer to watch. At the tail end of the season when frosts are threatening, this argument of the increased weight of tomatoes which are red ripe all over of course loses its effect entirely. All the farmer is interested in at that time is in getting as many of his tomatoes as possible accepted before a heavy frost finishes them. At this time increased vigilance at the receiving end is necessary.

Careful Handling at Factory

The less handling crates or baskets of tomatoes receive, the better. Every packer wants to eliminate handling as much as possible to conserve labor, but when one sees the laborers around the average plant heaving crates of tomatoes around as though they were pig iron, he wonders if the manager fully realizes the effect of this bouncing of heavy crates of tomatoes on to trucks, receiving platforms, etc. It is just as easy, or almost as easy, to set the crates down gently, but the laborers who do this work must be constantly reminded of it. You do get tired of constantly hammering at them, but it is surely worth the effort. A common attitude for the men to take is that the tomatoes are all going to get mashed up anyway pretty soon, so what’s the difference. When you consider the fact that crates of tomatoes are commonly handled from six to eight times before they reach the sorting belt, this handling often consisting of dropping the crates down so hard that the top tomatoes almost bounce out, it is no wonder that when they are spread out on the sorting belt the bottom layer of each crate is mashed and moldy, so that half of these bottom tomatoes have to be thrown away.

Varieties

Any of the brilliant red varieties of tomatoes are suitable for catsup or pulp making. Those varieties having a purplish cast should be avoided, as they cook up into a product having a brownish color. The smooth, round varieties, such as the Stone, are especially good for peeling, while the flat varieties, and those having a very coarse, uneven surface, are well suited for pulp or catsup.

Storing Tomatoes

For storing the tomatoes at the factory until they can be put over the sorting belts the open-air storage is used almost universally, and it seems to be the only method which can be economically employed at a plant which handles large quantities of tomatoes. I have seen the wet storage method in use at a small plant where the receipts only amount to a few hundred bushels a day on good days, and less than a hundred on many days when the weather is very bad, and it was liked very much by the plant manager. The tomatoes, as soon as received, were dumped into a large concrete tank of cold water, which was kept fairly fresh by letting fresh water run into it constantly, with an overflow at the other side of the tank, and a large revolving paddle at one side of the tank kept the water in motion. Attached to this paddle was a series of flights on an endless chain, which, when thrown into gear, carried the tomatoes to the sorting belt.

The argument advanced in favor of the wet storage method by the operator of this plant was that at certain times in the season their receipts of tomatoes were very small, that is, at the beginning and at the close of the season, and during stretches of cold, rainy weather, and at such times they only made a run every other day, or possibly only twice a week, and that the tomatoes kept much better in wet storage.

The tomatoes were clean when delivered to the sorting belt, and although they received very little sorting, and only one spraying after they left the storage tank, the count of molds, yeasts and spores and bacteria on their pulp was fairly low.

The wet storage method could undoubtedly be used at large plants, and might prove profitable during periods of glut, as there is no doubt but what tomatoes will keep better in wet storage than in the open air. It would take a lot of tanks for a large plant, however, and large operators are not inclined to look favorably on the idea.

In open-air storage the crates of tomatoes should be stacked so as to leave an air space between each crate, and if stacked inside of a building, all the windows and doors should be thrown open to allow as free a circulation of air as possible.

Stemless Tomatoes

Most tomatoes are delivered to the factory with the stems on, but I know of one plant where they are all received stemless, and the quality of the pulp made from them simply cannot be beat. There surely must be an undesirable taste imparted by all these green stems in the cooking process. Of course, where the cold pulping process is used, that is, the tomatoes pulped cold directly after sorting and washing, these stems are eliminated before any cooking is done. In the hot pulping process, however, and when the tomatoes are put in a crusher instead of a pulp machine, the stems are cooked along with the rest of the pulp. The operator of the plant referred to above pays a bonus of a dollar a ton to his contractors for having the tomatoes delivered stemless, and he believes he gets that dollar back and more, too, in the price he gets for his product, which is very fancy.

CHAPTER II
WASHING AND SORTING

Washing and Sorting Equipment

A great many outfits for washing and sorting tomatoes have been placed on the market, some of which have many good points, and others are very inadequate. The type of washer best adapted to one plant may not be the best for another one. If tomatoes are grown on clay ground a friction washer is necessary, while for fruits grown on sandy soil it is very infrequent that much friction is needed to properly clean the tomatoes.

As to sorting belts, as a rule one type will serve as well in one place as in another. A majority of the sorting belts used are subject to many criticisms; some are too narrow, some too short, some travel at a speed of 100 feet or more per minute, while others move as slowly as 10 feet per minute. The latter speed is much better than the former, although both are extremes, 25 feet per minute being about right.

Rotary Washer

For tomatoes grown on clay ground the cylindrical rotary washer or squirrel cage type made of 1–inch mesh heavy wire is very satisfactory. When tomatoes come to the plant caked with clay, as they are after a hard rain followed by strong sunshine, a friction washer of this type is about the only thing that will clean them. This type of washer also does excellent work on late tomatoes, and this applies to all localities. A large percentage of late tomatoes become deeply cracked at the stem end, and although these cracks, or fissures, usually appear to be healed over, an examination will generally reveal the presence of mold in them, and in many cases large tufts of mold like cotton completely filling them. By merely passing such tomatoes through a water bath, even though the water is thoroughly agitated by means of many inlets of compressed air, this imbedded mold will be scarcely affected. A rotary, heavy wire, reel washer, inclined at an angle of about 1 foot in 8, and rotating slowly, with a heavy, sharp spray of water striking the rolling tomatoes from the time they are dumped in until they roll out, will take out a very large proportion of this mold, besides cleaning the entire surface of the tomato thoroughly.

The washer should deliver about two bushels of tomatoes per minute to the sorting belt. As the wire cylinder revolves, the tomatoes are carried half way up the side and are then thrown back again, being carried slowly and steadily toward the outlet. A 1½-inch pipe at the top of the cylinder, and running from end to end, with small holes bored at intervals of an inch, should direct a sharp, cutting shower of water on the tomatoes as they revolve and rub each other. A fine, sharp spray will accomplish more than a less forceful but larger stream of water coming from a larger opening. The dirt, mold, etc. is washed through the wire mesh into a drip pan, and thence to the sewer.

Some of the rotary washers used are of solid metal, and others constructed of wooden slats have been used. Both of these should be avoided, as the solid metal produces a sliding, instead of a rolling action, and the wooden slats mold quickly and become slimy. Also, some of the washers are slightly too narrow, and the tomatoes are so crowded while they are rotating that many of them do not come in contact with the wire, but merely roll on top of other tomatoes. Other washers are considerably wider than necessary. If the tomatoes are to be fed to the belt at the rate of 2 bushels per minute, a reel (squirrel cage) washer 2 to 2½ feet in diameter, and about 8 feet long, having an inclination of about 1 foot in 8, and revolving at about 20 revolutions per minute, will usually give satisfactory results. These are the figures recommended by Mr. Howard of the Bureau of Chemistry, who has made a very extensive study of the efficiency of rotary washers.

By having the tomatoes thoroughly clean, with no mud and scarcely any mold adhering to the surface when they drop on the sorting belt, the amount of sorting required is not only greatly lessened, but the spots of black rot and other forms of decay show up prominently on the surface.

It is important that the reel deliver the tomatoes to the sorting belt at a uniform rate, which is seldom done when the crates are dumped into the reel without any system of timing them. At present a hopper for feeding the reel is being experimented with, and it is hoped that it will be an improvement over the uncontrolled system that is now used.

The chief objection made to the reel cylinder is that when tomatoes are overripe, having been shipped a long distance, or held at the factory for a day or two, the rubbing action of the wire on the tomatoes, and of the tomatoes against each other, is too severe, and considerable tomato substance is lost by being forced down through the wire mesh by the sharp sprays of water from overhead. The loss in this case is not nearly as great as would be imagined, and what tomato substance is thus lost should be discarded anyway, as it is so soft that in all probability the fiber is permeated with growths of mold, yeasts, and bacteria, which no amount of washing would eliminate.

Water Bath With Compressed Air

The reel washer is not so common in the east as in the west, and the reason is, as previously stated, that during the greater part of the season at least, tomatoes grown on loose, sandy soil can be washed satisfactorily by other devices which are less cumbersome and can be more easily rigged up. One of these devices which is in satisfactory operation is a shallow water bath through which the tomatoes pass on a chain carrier, and in which the water is kept “boiling” (that is, it has the appearance of boiling) by compressed air which is forced into the water bath through small pipes, and at a number of different places. The tomatoes are thus bounced around and knocked against each other in a very lively manner and receive a thorough cleansing. It is very doubtful, however, if this device would give such good results on tomatoes that had clay baked hard on the surface, or on those which had mold deeply imbedded in cracks at the stem end.

Importance of Agitation

It is always advisable to wash the tomatoes before sorting them, as it makes the sorter’s work so much easier. After the tomatoes leave the sorting belt they can pass under a few strong sprays which will put on the finishing touches. Warm or hot water is sometimes used in washing tomatoes, but cold water does the work just as well. Neither will accomplish much more than wetting the surface unless the tomatoes are agitated. Some devices which I have seen are almost worse than nothing, as they merely consist of a long water bath through which the tomatoes are conveyed by means of a large worm or helicoid. The tomatoes are not only washed insufficiently, but are contaminated by rubbing against the surface of the worm, which soon becomes coated with a film of mold, and, being enclosed in a cylinder, this worm cannot be cleaned as it should be. It is essential that every part of the equipment with which the tomatoes come in contact be readily accessible to the brush and the steam hose. Mold accumulates very rapidly, clings very tenaciously to the surface on which it grows, and a damp surface in a dark place is ideal for its growth.

Plain Sorting Belt

The type of sorting belt used most commonly is the ordinary plain wire or metal belt 18 to 24 inches in width and about 10 to 12 feet in length. Canvas belts are also used quite frequently, but the packer can now obtain wire belts of such strong, sturdy construction that they give scarcely any trouble and are very satisfactory in every way. Eighteen to twenty inches has been found to be about the best width.

Number of Sorters

The number of sorters which should be employed on each belt depends upon whether they are going to do both the inspecting and trimming, or the inspecting alone, and also upon the rate at which the tomatoes are fed to the belt, the length of the belt, and the quality of the fruit. Some pulp makers prefer to feed the belt at a uniform rate regardless of the quality of the fruit and to vary the number of sorters, employing about 14 or 16 to a belt when the quality is poor, and about half that number when the tomatoes are almost entirely sound and need very little trimming done to them. Others prefer to use the same number of sorters and trimmers on the belt all the time and to vary the speed of the belt according to the quality of the fruit, using a variable speed transmission for this purpose. When running on solid fruit, with very little decay, the maximum speed can be employed, say 40 feet per minute, and when running on stock that is not so good the speed can be decreased to about 10 feet per minute.

The Bureau of Chemistry advises very strongly against the practice of having the women who do the inspecting do the trimming also. They contend that inspecting and trimming should be two distinct and separate operations and each should be done by a different set of women. By this method the women on the sorting belt merely pick out all the tomatoes which are imperfect and throw them into receiving boxes which are attached to the framework of the sorting belt by a bracket, there being about four of these boxes to a table—two on each side. One or two women stand at each receiving box, pick out the defective tomatoes from this box, and trim out the bad part, which is dropped into a chute, which directs the material down to a drain underneath the table through which is flowing the waste water from the rotary washer. This stream, properly placed, has sufficient current to carry away the waste matter. The trimmer throws the good part of the tomato back on to the sorting belt. By using this system there is no lugging of boxes or buckets back and forth from the sorting table.

This method, which is the one approved by the Bureau of Chemistry, accomplishes the work more thoroughly than can be done if the inspecting and trimming are all done on the sorting belt by the same set of women. The minimum cost of sorting and trimming in this manner is from 2 to 3 cents per bushel, according to the government figures.

If the women on the sorting belt are to be used for both inspecting and trimming, a longer belt should be used than if inspecting alone is to be done. About 2 feet of belt should be allowed to each sorter.

Tomato Turning Device

Fig. 1.—Tomato turning device on sorting belt.

There is another feature which helps greatly in sorting, and that is a tomato turning device, which is illustrated in Figure 1. This device turns a very large percentage of the tomatoes if they are fed to the belt properly, that is, if they are spread out evenly and are not too thick on the belt. The turning device allows them to be inspected from all angles, and is described in Bulletin 569 of the U.S. Department of Agriculture as follows:

“For an apron (sorting belt) 18 inches wide, 14 pieces of ¾ inch iron pipe (1 inch outside) were cut, each piece about 7 inches long. About one-half inch from one end of each piece a hole was drilled through the pipe large enough to permit of the pipes being strung on a ¼ inch steel rod. In order to insure freedom of movement, a thin washer was placed between each pipe and the one next to it. The whole set was then suspended by means of the steel rod across the sorting apron with the lower ends one-half inch above the apron. A back-stop rod is put in behind the set to prevent the pipes from swinging back past the center. This was found necessary to prevent them from swinging so far back as to strike and gouge the oncoming tomatoes. * * * In operation the weight of the pipes is sufficient to roll the tomatoes over as they pass under.”

“In order to obtain satisfactory operation it is most important that the tomatoes do not cover more than 50 per cent of the apron area, otherwise they do not have room to turn properly. A test at one plant showed that 70 to 80 per cent of the tomatoes were turned each time they passed under a set of the pipes. It was found also that this turning device worked better on the open metal apron than on the canvas or rubber type, owing to the fact that the tomatoes slipped badly on aprons made of canvas or rubber.”

Divided Sorting Belt

There is a modification of the plain belt which is in use at several plants, and which some operators like very much. This belt is illustrated in Fig. 2. Note that it is divided into three partitions by two boards which run lengthwise. These boards are about 3 inches high and are raised a fraction of an inch above the belt so as to allow the belt to slide under them easily. At the head of the belt the board partitions connect in a “V”. The tomatoes strike this V and are guided into the two outer channels, where they are given a hasty inspection by the first four sorters, who throw all those which are perfectly sound into the center partition. As the tomatoes which remain in the two outside partitions pass down to the rest of the sorters they are inspected, the bad parts cut out, and the good part thrown into the center partition. The bad parts which are cut out are left on the outside partitions, where they are carried along into two waste barrels, which are provided for this purpose at the end of the belt.

By using this method no tomatoes but good ones can go through unless bad ones are carelessly thrown into the center partition and every tomato HAS to be picked up. Of course, some bad tomatoes are thrown into the center carelessly, where they will remain unless taken out by the final inspector, who is supposed to watch this. However, the number which are thus thrown in are not great if the first four women on the belt are trained as they should be—that is, to only throw those tomatoes in the center which a hasty inspection shows are perfectly sound, and to leave all doubtful ones pass by.

By this method each good tomato is only inspected once, which is not the case with any of the other systems, and in that respect it is more efficient. One good tomato is not picked up, looked at, and placed on the belt again by a number of different sorters. When a tomato is picked up by a sorter some disposition is made of it at once. If good it is tossed in the center and is never looked at again except by the final inspector. If bad, the good part is thrown in the center and the bad allowed to remain on the outside, to be conducted to the waste barrel. All the sorters except the first four can spend their entire time working on tomatoes which need to have bad parts cut out of them.

The main objection which is made to the divided belt system is that the first four women get careless and throw unsound tomatoes into the center partition and they are never looked at again. However, if care is used in the selection of these women, and a reliable sorter is placed at the end of the belt to inspect the center partition before it leaves the belt, such carelessness can be checked and held down to a minimum. Another objection that is advanced is that there is the possibility of partly good tomatoes going into the waste barrels due to the fact that the women might not always keep up on them. In my experience with the system I have had practically no trouble in this regard. If a long belt is used, as many trimmers as desired can be put on, and the belt can be slowed down or the rate at which it is fed slowed up if the tomatoes are running particularly bad. Then, in extreme cases, it is always possible to have someone go over the waste barrels before they are dumped.

An average grade of tomatoes can be handled quite rapidly by the divided belt system. Some packers who have used it several seasons like it very much, and an analysis of their product will generally show a low count of molds, yeasts and spores, and bacteria. I understand, also, that other packers that have used the method have discarded it.

Sorting

By far the greater part of the trouble packers have with their goods not complying with the government regulations as to molds, yeasts and spores, and bacteria is due to inadequate sorting. At least ninety per cent of this trouble could be overcome right at the sorting belt. Packers often say they can’t understand why the mold is running high on their pulp and catsup, as they are sorting their tomatoes carefully. However, the chances are ten to one the trouble is they are not sorting them carefully enough. One who has not had much experience managing help on the tomato sorting belt would imagine that almost any woman could step up there and sort out the good tomatoes from the bad, and know what to cut out, and what not to cut out. But such is not the case. The tomato sorters must be instructed. Someone who is competent to do so must work with each one of them and show them just what is a good tomato and what is not. Otherwise they will be spending part of their time cutting out black, fibrous growths on the surface of the tomatoes which are absolutely normal and entirely free from molds, etc., and allowing tomatoes to pass by them which have black spots on the surface no bigger than a dime, but indicating to the trained eye that probably half of the tomato is eaten up with black rot. They will allow a tomato to pass by which is cracked open, and the edge of the skin on each side of the crack will be as white as a piece of paper. Unless they are instructed, they may not realize that this is mold, and they certainly will not realize the amount of damage a small percentage of tomatoes like that can do. They know nothing about mold counts, but most women can be impressed with the importance of watching for moldy streaks and spots in mashed and split tomatoes, and the importance of eliminating every bit of tomato tissue that is so effected.

Every sorting belt should have a boss—a competent sorter who knows his or her business, and who stands at the end of the belt and inspects the tomatoes just as they are about to leave the belt. This person can order the speed at which the tomatoes are fed to the sorters increased or decreased according to the quality, can see just what form of decay is predominating and caution the sorters to watch out for it, can see the mistakes that are being made in the sorting and try to correct them, and in addition can throw out into a receptacle such bad tomatoes as have passed by the sorters so that they can be sorted over again. It is not safe to put a bunch of women on the sorting belt with no one in authority who is on that particular job every minute, and expect an entire day’s run to come within the government limits.

Forms of Decay

There are many forms of rot, but the most common are the black rot, soft rot, and the mold growths in cracked tomatoes, either those which have cracked deeply around the stem end during their growth, or have been cracked or mashed in shipment. Just as soon as the skin is broken, either in a natural or unnatural way, molds start growing on that broken surface immediately, and develop very rapidly.

There is also the brown spotted tomato, which is not so common, but which has been very bad in some localities. I remember one field of tomatoes in southern Ohio several years ago which was absolutely worthless for canning purposes, due to the fact that practically all of the tomatoes were covered with brown spots, and under each one of these spots was a lump of white mold and mold spores. This field was plowed up before half of the tomatoes were picked, as the pulp plant which had contracted them refused to receive any more after having cooked several batches of pulp on which the mold ran very high due to this condition, which had never been met with before. The brown spots were soft and concave, and if once the character of the spot was fixed in the memory one could never fail to quickly detect that type of tomato if it was run across again.

The disease appeared in both central and southern Indiana the following year and I sent samples of the tomatoes to the Department of Agriculture at Washington and to the Indiana state experiment station, but it was new to them and they had no remedy for it. Whether it has appeared since I do not know, but it was very bad while it lasted. It is almost impossible to sort such tomatoes, as the spots are so numerous on the surface, and every spot would have to be cut out. When the spots are small, as they frequently are, they are very apt to pass by the sorters unnoticed, or at any rate considered harmless, but it doesn’t take many bushels of such tomatoes to send a batch over the limit in mold count.

Extremely soft spots which will yield to very slight pressure with the finger are usually receptacles for the growth of yeasts and bacteria and should be cut out. Nine times out of ten such spots are offensive to the nose when the skin of the tomato is broken. However, one quickly learns to pick them out by sight.

It is important that the sorting belt be well lighted with 100–watt lamps overhead provided with large reflectors. On dark days good sorting is impossible unless the belt is adequately lighted, and, of course, for sorting in the early morning or late evening adequate light is absolutely essential.

Cleanliness of Equipment

To dwell upon the necessity of thoroughly cleaning all washing and sorting equipment each night, as well as to frequently change the water in water baths, in case a water bath is used, would seem almost unnecessary, yet there are many packers who do not comprehend the trouble that can be caused by inadequate cleaning of the washing, sorting, and conveying equipment.

Does the sorting and washing equipment in every pulp plant impart a clean, fresh, sweet smell when the morning’s work is begun? It does not, and the reason is that it was not properly cleaned the night before. Those surfaces which were easy to get at and which are easily seen in a hasty inspection are clean, of course, but how about the dark corners and almost inaccessible places that are hard to clean? Can you run your fingernail over the surface of one of the bucket conveyors, or “flights,” for example, and scrape off a thin, slimy film? If you can, you can be sure it is mold, and that the only way to get it off is with a very stiff brush—even a wire one may be necessary—hot water, and soda ash. If the bucket conveyors or “flights” are covered with a thin film of mold, the tomatoes will carry along a small part of this mold with them every time the conveyor is used, and as fast as the mold is rubbed off the conveyor by the tomatoes more mold will grow on again.

The same care should be taken with this equipment as is given to the equipment in a milk bottling or condensing plant. My experience has been that the only safe way to check up the thoroughness of the cleaning job is to go over it with a spot light, with particular attention to the most inaccessible parts, and to do everything possible to make every part of the equipment accessible.

Molds, Yeasts and Spores, and Bacteria

An understanding of the nature of molds, yeasts and spores, and bacteria is very helpful to any packer. A knowledge of the rapidity of their growth and the conditions under which they multiply most rapidly is also helpful. The average packer has a very vague idea of this subject, yet it is easy of comprehension. In CHAPTER VII a discussion of it will be found, which it is hoped will help to clear up the misty atmosphere surrounding this subject, and in the same chapter the government attitude toward micro-organisms is also discussed.

CHAPTER III
PRINCIPAL METHODS IN USE FOR PULPING

The chief methods in use for preparing the tomatoes for the cooking kettle are: first, cold pulping; second, hot pulping; third, crushing without cycloning.

Cold Pulping

The cold pulping method is probably the most common, and requires less equipment than the hot method, with results that are considered by many packers just as good, if the pulp machine is operated by a careful man who will not feed it too fast, and who will keep it clean. Sometimes, with this method, the tomatoes are run through a crusher before pulping, and sometimes not.

Care of Cyclone

It is important that the outlet from the receiving box under the cyclone be directly from the bottom, and not from the side of the box near the bottom. The box must drain completely so as not to leave any tomato juice lying in it to ferment. A tapering enamel lined receptacle which drains itself completely is best to use under the cyclone.

The steam hose should be turned into both the cyclone and receiving box several times during the day to arrest growths of micro-organisms, and clean out adhering tomato fiber. It is particularly important to do this just before the noon hour, as considerable fermentation can take place in the cyclone during that hour if it is not cleaned out beforehand.

Hot Pulping

By the hot pulping method the tomatoes are conveyed, usually by means of a series of “flights,” or a bucket conveyor, to “breaking tanks” which are arranged above the cyclones. These “breaking tanks” hold about 1000 gallons, and are usually constructed of cypress. At the bottom of the tank are open brass steam pipes running horizontally in four directions. These pipes are about two feet in length, and are open at the ends so that the steam comes directly in contact with the tomatoes. The tomatoes are conveyed direct from the sorting belt to the “breaking tanks,” and as soon as the brass pipes are covered the steam is turned on full and the breaking up process begins. It usually takes about 30 minutes to break up the tomatoes, and they are then cycloned. The tank should have a concave bottom and large outlet, preferably 3 inch, so that the broken up tomatoes can be let out of the tank easily. Iron pipes should, of course, be avoided, as the acid of the tomato attacks the iron, producing an iron salt which is apt to discolor the product, particularly if it is to be used for catsup, and this dissolved iron comes in contact with the tannic acid of the spices. This will be discussed further under the manufacture of catsup.

Some packers object to brass and copper coming in contact with the tomatoes on account of the slight amount of copper which goes into solution by the action of the tomato acid. In the case of the “breaking tank,” however, the few short brass pipes offer a very small surface to the action of the tomato acid, and the amount of metal dissolved would be negligible. These brass pipes can be plated with tin if it is desired to avoid contact with brass altogether, and this is frequently done.

Advantages Claimed for Hot Pulping

Those who use the hot pulping method like it for a number of reasons. In the first place, the tomatoes are brought to a boil while they are still whole, and this eliminates any chance of fermentation due to the crushing of the tomatoes before they are cooked. By bringing the tomatoes to a boil quickly, that is, as soon as the washing and sorting is completed, any incipient fermentation is arrested immediately. As the tomato juice is near the boiling point when it is cycloned and delivered to the cooking kettles, no multiplication of yeasts, bacteria, etc. can take place between the sorting and the final condensing, unless the juice is allowed to cool considerably at some point between the “breaking tank” and the cooking kettle.

Another advantage claimed for the hot process is that the pulp of the tomato is more completely separated from the seed and skin than when the tomatoes are pulped cold, and therefore the tomatoes will give a slightly larger yield of pulp. It is also claimed that a better color can be obtained by the hot pulping process, as the color cells of the tomato lie in greatest abundance directly next to the skin, and by making a clean cut separation of the skin from these color cells by boiling in a “breaking tank,” none of this color will be lost in the pumice during the cycloning. Although this argument does appear reasonable, I have failed to see that tomatoes which are pulped by the hot process give any better color than those which are pulped cold.

The hot process is also liked where the tomatoes are to be manufactured directly into catsup or tomato soup, as the “breaking tank” can be filled up to a certain mark with the boiling tomatoes and that gives the measure of tomatoes for the catsup or soup batch, and no other measuring devices for this purpose need be employed.

Objections to Hot Process

The chief objection to the hot process is that it requires a lot of additional tanks for breaking the tomatoes, which are entirely dispensed with when cold pulping is used. The tanks are not only an additional expense to the equipment, but require one or two operators to tend to them, and they take up a lot of room, and consume a lot of steam. No seed can be saved from tomatoes which are pulped hot, as the cooking either kills the germ or renders it impotent. Quite a few canners save the seed from cold pulped tomatoes, and the revenue from it proves to be a profitable item.

As to whether the slightly increased yield to be obtained by the hot pulping method, and the decreased danger of multiplication of yeasts and bacteria, more than compensate for the advantages to be obtained by the cold process is a question which the individual packer must decide for himself.

Crushing

Crushing the tomatoes without cycloning them is a very good method where the tomatoes are going to be made into pulp or puree, as the finishing machine will convert the crushed cooked tomatoes into a very smooth product. Where catsup is to be made direct from the tomatoes, however, cycloning is to be preferred to crushing. If the final product is to be soup, cycloning is necessary. This will be discussed further in the chapters on catsup and soup.

When a crusher is used it takes the place of the cyclone or pulp machine, although it performs an entirely different kind of an operation, and the tomatoes go through exactly the same process as in cold pulping, except that instead of removing the seeds and skins from the tomatoes before cooking, the tomatoes are chopped very fine and conveyed to the cooking kettles—seeds, skin and all. It is obviously somewhat harder to gauge the finishing point of a batch of pulp where the skins and seeds are present, however a little practice largely eliminates this difficulty, and there is always the method of determining the specific gravity by weight to fall back on. The seeds and skins will not interfere with making the specific gravity test as it is usually carried out in the cook room with a large copper flask, small trip balance, and set of weights.

Conveying to Kettle

If the plant is so arranged that the pulped or crushed tomatoes can be conveyed to the cooking kettles by gravity, that is an advantage, as it does away with a pump and someone to tend to it, and the fewer the pumps, the better; however, in most plants it is necessary to pump the pulped or crushed stock into the cooking kettles. Unless the plant consists of several floors and the tomatoes start at the top and come out as finished pulp at the bottom, or the plant is built on a terraced plan, as one plant is in Indiana, which is built on the side of a hill, it is necessary to do a certain amount of pumping. An ordinary pump will not do, as there would be contamination by iron, and considerable rusting, while the pump was idle, of those parts of the pump with which tomato juice comes in contact, this rust to be carried along with the tomato juice the first time the pump is used again. The rotary pump constructed partly of bronze or nickel is very good for this purpose, and offers as little opportunity for metallic contamination as any pump does.

The pipe used for the conveying of this tomato stock should by all means be enamel lined. Enamel lined pipe, if properly made, will last for many years without chipping or cracking. Just how long it will last on the average I cannot say, but I have often taken down lines of enamel lined pipe that have been in use for several years, and it looked practically as good as new. The flanged pipe with flanged fittings is better than that with the ordinary screw ends, as it makes practically a continuous white tube without any pipe threads in which molds, yeasts, and bacteria can lodge and multiply.

Wooden troughs are still used in many plants for conveying tomato juice and pulp, but they are a relic of the old days, and have no place in the modern pulp or catsup plant. Wooden troughs are hard to keep clean, they mold very quickly after they become damp, they are open to contamination from ceilings and roofs which aren’t always in good condition, and they are usually wasteful. It will pay any packer who still uses even a few wooden troughs to invest in enamel lined pipe. Wooden pipe is also unsanitary for this purpose, as mold grows in it and clings so tightly to the porous, damp surface that it cannot possibly be flushed out.

Value of Pumice

This chapter, which deals principally with cycloning, seems to be a fitting place to discuss the value of the pumice which comes as a waste product from the cyclone. Although it has been repeatedly demonstrated by chemical analysis that this pumice or tomato waste is a valuable by-product, every time the question has come up of its utilization and preparation into a salable product or products, the decision has been that the expense involved would be too great to make it pay. This by-product is profitably handled in Italy, producing an oil of commercial value, and an oil cake which is used for stock feed; however, the conditions in Italy and in this country are very different. In the Parma district of Italy there are forty factories very close together, and little expense is involved in bringing the waste to a central point where enough of it can be had to keep a drying outfit and an oil press or oil extraction outfit busy. Labor is also very cheap and plentiful, and there is a ready market for the product, the oil being used as a soap stock, and the oil cake finding ready sale as a stock feed. In this country, however, there is not enough waste at even one of the largest plants to pay for the operation of a drying outfit and the pulp plants are so scattered that hauling or shipping charges to a central point would be expensive. Furthermore, labor is scarce and expensive.

That quite a little labor is involved in the preparation of the waste is soon discovered by a little experimenting. As the waste ferments quickly it must be handled as produced, or preserved in some way, which would be a questionable operation, as the oil cake is used for stock feed. As the skins are practically valueless, they must be separated from the seeds in which all the value lies. This separation can either be carried out in the moist state by a gravity separation in water, in which the seeds, being heavy, sink, and the skins float; or by the use of a fanning mill after drying, in which case the dried skins, being very light, are blown out. Before drying either the seeds alone or the unseparated waste, the excess moisture must be pressed out with a hydraulic press. The pressed product must then be broken up and put through a steam or hot air dryer of the rotary, cylindrical type. After the seeds are dried to a 10 per cent moisture basis they must then be ground, and the oil extracted either by pressure, or by dissolving it out with a chemical agent, such as carbon tetrachloride. The oil cake which remains would then be sacked for stock feed.

This briefly gives an idea of the labor involved, and the difficulties surrounding the situation. It may be successfully worked out some time, but will require close co-operation from a number of large pulp plants which are near each other to be a success. Some plants are giving the waste to farmers if they will haul it away, and I know of one farmer who has for years fattened a bunch of hogs cheaply during the tomato season in this way. It is a queer thing, though, that most farmers turn up their noses at the idea.

The seed, when dried to a 10 per cent moisture basis, contains about 23 per cent protein and from 20 to 25 per cent of fat. After the fat is extracted the protein in the cake will run close to 30 per cent.

In a test made by the U. S. Department of Agriculture the ground cake ran 37 per cent in protein, which puts it in about the same class with cottonseed meal. They also refined some of the oil and are of the opinion that it has the qualities of an edible oil.

If a factory uses the cold pulping method the most profitable way to handle the pumice is to ferment it and then separate the seed and dry it, and use it for planting the following season. Care must be taken, however, to keep out undesirable strains and varieties foreign to the one which is being grown.

CHAPTER IV
CONDENSING THE STRAINED OR CRUSHED TOMATOES

Vacuum Pan

Practically all of the tomato products made in this country are cooked in an open kettle under atmospheric pressure—either a copper-jacketed kettle, or a tank with a closed coil. The vacuum pan is used, however, in several plants, and makes a very high grade product—a better product as a rule than can be made by condensing under atmospheric pressure. When tomato juice is condensed in vacuum it boils at anywhere from 54 degrees F. to 175 degrees F., depending upon the degree of vacuum obtained. At sea level, under atmospheric pressure, it boils at 212 degrees F. By employing a low temperature, and condensing rapidly, which can be done in the vacuum pan, the natural bright red color of the tomatoes is affected very little by the cooking. High temperatures and continued boiling are the agents which destroy tomato color as well as flavor. The vacuum pan produces a pulp of not only fine color, but of very fine flavor. The reason the vacuum method is not used more frequently than it is is undoubtedly due to the difficulty in getting the vacuum equipment, and also to the expense of the equipment when it can be obtained.

Types of Open Kettles

The open kettle method produces a very satisfactory product when the proper precautions are taken, and if the cooking and subsequent processes are carried out intelligently, the finished product compares very favorably with that which is condensed in vacuum. The types of kettles in most common use are the copper jacketed kettle, the glass-lined tank with closed copper coil, and the cypress tank with closed copper coil. All of these give good results where the jacket or coil is properly constructed, the steam trap is of the right type and takes care of all of the condensation without allowing it to back up into the coil, and the kettle has a good head of steam so that a vigorous boil can be maintained throughout the cooking.

Steam Pressure

If the steam pressure at the boiler is kept above 75 lbs., and too much is not lost by radiation from uncovered pipes, and by leaks at poorly packed flanges, etc., there should be no difficulty in maintaining a vigorous boil. The evaporation should be so rapid that the vaporizing steam will burn the hand, even if placed over the kettle for a second. If you can hold your hand over a kettle of boiling pulp, even for a few seconds, you can be sure that you are not getting a proper boil. A pressure of 100 lbs. is, of course, to be preferred to 75, as it will effect a quicker condensation, however there is not a large percentage of boilers in tomato pulp plants that are permitted to carry as much as 100 lbs.

The kettles should be close to the boiler room, and the steam pipes feeding them should be as straight and short as possible, and covered with magnesia pipe covering to prevent excessive loss of heat by radiation. It is not an uncommon sight in canning plants to see the main pipe from the boiler to the cooking kettles pass through an areaway between two buildings, and have no protective covering whatever. Such sights, however, are becoming more infrequent, as packers are plugging up many of the leaks through which dollars have escaped every day in years gone by. The condensation from the steam traps can, of course, be used right over again in the boilers.

Copper-Jacketed Kettles

Copper-jacketed kettles used for condensing tomato products range all the way from 50 gallons capacity to 500 gallons, the larger size making a batch of finished pulp of about 250 gallons as a rule. A larger batch than this can be cooked in a 500–gallon kettle, but it is not advisable to keep pumping fresh tomato juice into the kettle too long, as it gives too long a cook to the first that goes in. Forty-five minutes should be the absolute limit for a batch of pulp, no matter what kind of a kettle it is cooked in, and it is much better to confine the cooking time to 30 minutes or less. The shorter the cook, the better the color and flavor of the finished product, other things being equal.

Tinning Kettles

Copper kettles are frequently lined with block tin to prevent the acid of the tomato from dissolving some of the copper. The desirability of this is argued both from a standpoint of health and flavor, as dissolved copper, even in small quantity, has a very bitter taste. It should be remembered, however, that the acid of the tomato, which is generally thought to be citric acid, is a weak organic acid, and the amount of copper dissolved in a batch cooked not over an hour is exceedingly small; certainly so small as to have no ill effect upon health. As to the question of flavor, it would indeed take a very delicate palate to detect among a half dozen samples which ones were cooked in an unlined copper kettle, and which in a kettle lined with block tin or silver. The latter is said to be used by some packers.

It is a good idea, however, to play safe, and line all kettles with block tin, as we know that there is a small amount of copper taken up in solution in the pulp. This is more important in the case of catsup and chili sauce than where the kettles are used for pulp alone, as vinegar and salt act on the copper much more severely than tomato acid does. As to the thickness of the block tin lining, an inspection of the kettles used by various packers shows this to run all the way from a good half-inch thick to a coating so thin that in one season’s use it is almost all scraped off by friction in cleaning the kettle. The kettles should be plated heavy enough to last several seasons without re-tinning, however a coating a half-inch thick is unnecessary and wasteful of steam. The same remarks apply to the tinning of copper coils.

Advantages of Various Types of Kettles

Although copper-jacketed kettles have the advantage of being very easily cleaned, and also the advantage of wasting very little of the product when the finished batch is being discharged, the large tanks of either cypress or glass-lined steel are coming into use more and more because of their greater capacity. It is true that they are very slightly more wasteful than the jacketed kettles, but this really amounts to very little if the tanks are built with a concave bottom. They take up no more room than the jacketed kettles, and will hold a much larger volume, as they can be built so much higher. If one were to buy a series of copper-jacketed kettles to cook batches as large as are commonly cooked in tanks equipped with copper coils, the expense would be very heavy, there would be much exposure to metal, and the results obtained would be no better, or possibly not as good. In the tank equipped with a coil, batches of 300 or 400 gallons are often cooked, and the juice can generally be condensed to a specific gravity of 1.035 in 25 to 30 minutes.

Glass-Lined Tank

During the last few years quite a few packers, when adding to their cooking capacity, have put in glass-lined steel tanks. The glass-lined tank is equipped with coil and steam trap in the same manner as the cypress tank, and it has certain advantages which make it very nice to work with, even though the first cost is considerably more than that of a cypress tank of equal capacity. The only objection I have heard to the glass-lined tank is that it radiates more heat than a wooden tank, and on very hot days, unless it is insulated, makes the cook room more uncomfortable than the same capacity in cypress tanks would. However, when the tank is covered with cork insulation, or asbestos, or even wood staves, it radiates no more heat than a cypress tank.

The glass-lined tank is perfectly sanitary, and is very easily cleaned. It is really the most sanitary thing we have to cook in. The surface is smooth and entirely free from any irregularities such as there are bound to be between the staves of the cypress tank. It is always ready for use, and does not have to be swelled and then scrubbed for a half day after standing idle for a while before it is fit to use again. There are no places for molds to creep in and multiply. Furthermore, being of metal and all in one piece, a battery of glass-lined tanks will not shake like cypress tanks will when you are running heavy and have several tanks going full blast at the same time. This may seem rather unimportant, but it is quite a relief to the cook and his helpers, as they can go about their work without having their nerves rattled. Just how long a glass-lined tank will last under average conditions in a pulp or catsup plant is not known, as they have not been in use a great many years for this purpose; however, one would guess that they would be serviceable almost indefinitely.

Cypress Tank

Cypress tanks should be constructed of 2–inch material and made with a sloping or concave bottom, preferably the latter. They will not impart any foreign taste to the product, as is sometimes thought, even after becoming charred by long usage, and if kept clean they will remain sweet as long as they are kept in continuous use. A musty taste is sometimes imparted to pulp or catsup cooked in a cypress tank if it has been standing idle for a long time and is not thoroughly cleaned and boiled out with soda before it is used again. Cypress tanks have the advantage of being cheap, and also of having large cooking capacity.

Cleaning Kettles

Cooking tanks and kettles should be cleaned thoroughly after every batch. If the steam trap is working properly the burning on the coils and sides of the kettle will be so slight that almost all of it can be washed off with the hose if the water pressure is strong and the hose is bushed down to one-eighth inch. The best things to use to take off the material which burns on hard and black is a pot chain for coils, and for the jacketed kettles a wire brush or very stiff fiber brush does very well. If any of the baked on pulp is not removed before the next batch is cooked it will interfere with the cooking by lengthening the time required to finish the batch, and by causing the coils to burn still harder next time. The cook should be instructed to get down in the tanks frequently, and feel underneath his coils to see that they are properly cleaned. The manager should also make it a point to do this several times a day. His quality will depend in no small degree on the way his coils are cleaned.

Coil Leaks

Leaks in coils should be attended to immediately, as they cut down the available steam pressure, and soon become so large that it becomes impossible to cook satisfactorily. An ordinary soldering job will only hold them for a day or two, and it is necessary to take out the coil and braze it if the leak is to be permanently mended.

Starting the Cooking

We will say that we are now pumping over the cycloned or crushed tomatoes into the cooking kettle. Some packers pour a cupful of cottonseed oil in the kettle to assist in breaking the boil, others rub the sides of the kettle with fat, such as a piece of cocoa butter, while others use no oil or fat at all, but take care to feed the kettle slowly and carefully, and cut the foam with a sharp spray of water from the hose to assist in breaking the boil. The oil or fat does seem to help some, but it is not necessary if the kettle is fed carefully. As soon as the coil or jacket is covered the steam can be turned on full; however, the exhaust should be opened immediately, and not closed until all the condensation which has collected in the coil or jacket runs out and the steam comes through perfectly dry. The condensation of the pulp should then be conducted as rapidly as possible, pumping over more of the tomato juice as the kettle is able to take care of it, and boiling continuously. The eye soon learns to judge the approach of the finishing point, and then the exact finishing point must be determined. There are many ways of doing this, and a number of ways have been recommended. No method can succeed which is not simple and quick, and which offers scarcely any chance for error when used by a cook, whom, it must be remembered, is a man of very ordinary intelligence.

Methods of Gauging Finishing Point

The simplest method is gauging the finishing point by the eye, but this method is also the least accurate in the hands of the average cook. Cooks who have had years of experience with tomato pulp sometimes get to be very expert in gauging the finishing point by the eye, and can determine it with surprising accuracy. Such a cook is the exception, however, and most packers have to use some sort of a mechanical method by which at least fair accuracy can be counted on. These methods consist of: first, condensing the pulp to a certain mark on the kettle, a definite volume of juice having been taken to start with; second, cooking a certain length of time; third, determining the specific gravity of the hot pulp by weighing a definite quantity on a small balance; fourth, estimating the gravity by the use of a hydrometer.

Cooking to a Gauge on Kettle

With the first method the amount of tomato juice pumped into the kettle, or the number of bushels of tomatoes from which this juice was derived, must be measured. This is a nuisance, and is not necessary with any of the other methods except the second. Furthermore, even though every batch of pulp cooked during the season be made from a measured quantity of tomatoes or tomato juice, and cooked to the same point on the measuring stick, the pulp will not all be of the same specific gravity, because tomatoes are very watery at some seasons of the year and very firm and solid at other times. The watery tomatoes will make a thin pulp, and the firm tomatoes will make a heavier pulp.

Cooking a Definite Length of Time

Cooking for a certain length of time is not dependable because the steam pressure is not always the same, the coils do not always condense the pulp with the same efficiency, and the character of the tomatoes varies during the season. With this method it is also necessary to start with a definite quantity of tomato stock for each batch.

Determining Specific Gravity by Weight

The third method—that of determining the specific gravity by weight—is used as commonly as any of the others. The specific gravity of pulp merely means the comparison between the weight of a definite volume of the pulp and the weight of the same volume of water at the same temperature. If pulp has a specific gravity of 1.035, that means that a gallon of it is 1.035 times as heavy as a gallon of water.

The determination, as carried out in the cook room, is made with a small trip balance, a set of weights, and a copper flask which is tin lined. The weight of the empty flask is taken. Then the weight of the flask filled to the top with boiling water is taken. The difference between these two weights is the weight of water at the boiling point which the flask contains. When the boiling pulp approaches the finishing point, the flask is filled to the top with the boiling pulp. This should be done rapidly, as the pulp cools quickly, and as it cools, decreases in volume. The weight of the flask filled with pulp at the boiling point is taken. This weight, minus the weight of the empty flask, equals the weight of pulp at the boiling point which the flask contains. You now have the weight of boiling water the flask contains, and the weight of boiling pulp the flask contains. Divide the former into the latter, and the result (the quotient) is the specific gravity. For example, if the water weighs 1,000 grams, and the pulp weighs 1,035 grams, the specific gravity is 1.035. If the specific gravity of cold pulp is taken, then cold water of the same temperature must be taken as the comparison. The weight of cold pulp must not be compared with the weight of hot water, and vice versa.

Objections to Weighing Method

One of the objections to the use of this method is that there is usually a certain amount of air bubbles and foam in the boiling pulp and this causes an error, as the air takes up volume but does not weigh anything. Another objection is that the determination is often not made rapidly enough, with the result that while the flask is being filled with boiling pulp, the pulp is cooling and correspondingly decreasing in volume, and by the time the flask is full, it contains more pulp than it should, that is, instead of containing 1,000 cubic centimeters of pulp at 210 degrees F., it will contain about 1,010 cubic centimeters of pulp at 200 degrees F., or possibly lower. One reason for this delay is that the foam caused by filling the flask with boiling pulp rises in the neck of the flask, and makes it hard to judge when the flask is exactly full. The main difficulty with the method, however, is that pulp cooks do not have scientific minds, they do not appreciate the importance of doing the determination in a strictly scientific way, and the results they get are not very accurate. I have frequently checked up on pulp cooks using this method, and sometimes they were very decidedly off.

Testing With Hydrometer

The estimation of the gravity of the boiling pulp by the use of a hydrometer is not in very general use, and it has been stated by some scientific men that a hydrometer is no good for tomato pulp or catsup except where the sample on which the test is made is previously filtered so as to get a clear liquid. A test which involves filtering, is, in my opinion, entirely unsuited for everyday use on the cooking platform.

I have used the hydrometer for testing pulp and catsup direct from the kettle for seven years, and have had more success with this method than with any other.

The hydrometer was never intended to be used with semi-solid substances such as tomato pulp, but only with liquids such as brine, sugar syrup, etc., in which there is no solid matter in suspension. With liquids, the number of degrees registered on the hydrometer when it is immersed in the liquid is equal to a definite specific gravity. This is not true with semi-solids such as tomato pulp, as each packer must work out the relation between the degrees of the hydrometer and the specific gravity on pulp under the conditions which obtain in his plant. This is a very simple thing to do, and once the packer has established this relation, it will hold good as long as he is in the pulp packing business. The reason why this relation is not the same for all packers is because tomato juice is not screened to the same degrees of fineness in all plants, and because all hydrometers having the same scale will not work the same on pulp. This is because they have different shapes. The shapes may only vary slightly, which will not interfere with their accuracy on clear liquids, but it will make a difference when the hydrometer is used in tomato pulp. Furthermore, some of the hydrometers will probably have too much variation in their diameter at different points, which is a disadvantage when they are used in tomato pulp. I have therefore always had the hydrometers which I have used for this test made to order and to conform to certain specifications which I laid down.

Fig. 3. Special hydrometer for testing tomato pulp and catsup.
(C. J. Tagliabue Mfg. Co.)

In Fig. 3 is illustrated a hydrometer which is manufactured by the C. J. Tagliabue Mfg. Co. of Brooklyn, and which is made to conform to these specifications, which are: first, perfect balance; second, a minimum amount of variation in the diameter of the various parts of the spindle with the slope very gradual; third, a Beaume scale reading from 0 to 50 degrees; fourth, that it can be obtained in exact duplicate in any quantity.

If the diameter at various points in the spindle is slight, with the slope very gradual, it seems to be an advantage. It is, of course, necessary that exact duplicates can be obtained to use when the first one, on which your calculations are based, is broken.

In order to avoid disappointments which would be very apt to result from the use of a hydrometer which was not particularly adapted to this test, and which would very likely be difficult of exact duplication, the type illustrated above should be adhered to, and it will be found to give good results when used as directed in this chapter.

Two pulps of the same specific gravity, and of practically the same degree of fineness, if tested hot, will register the same on the same hydrometer, or on two hydrometers which are exactly alike in every respect. (The hydrometer does not work well on cold pulp unless the pulp is thin.)

Two pulps of the same specific gravity, showing a very marked difference in their degree of fineness, will not register the same on the same hydrometer, because, even though a definite volume of each will weigh the same, the two pulps are of different thicknesses, which will have an effect on the degree to which the hydrometer will sink when placed in the pulp. However, if a packer cyclones his tomatoes before condensing them, and uses the same mesh of wire screen in his cyclone all the time, his pulp will all be of the same degree of fineness, and this point is eliminated. Every pulp packer who cyclones his tomatoes, and who uses the same mesh of screen in his cyclone throughout the season, can use the hydrometer for testing his pulp and can obtain uniformity without the use of any complex apparatus.

The relation between the hydrometer reading and the desired specific gravity is arrived at as follows:

When the boiling pulp approaches the finishing point, pour a sample into a tall gallon measure and take the hydrometer reading immediately. Save this sample, put it through the finishing machine along with several additional gallons dipped from the kettle so as to get a good sized sample through the finisher, taking care that the brushes are dry so as not to dilute the sample, and have the specific gravity determined on this finished sample when it gets cold. Take other samples from the kettle at five-minute intervals, and save them for the same purpose, after getting the hydrometer reading. We will say that one of these samples, when tested for specific gravity, ran 1.035. The packer looks up the hydrometer reading he got on this sample, when taken hot from the kettle, and finds the reading was 18 degrees. He then knows that for pulp of the degree of fineness he gets from his cyclone, 18 degrees on his hydrometer equals specific gravity 1.035 after finishing. He may also find that for the sample that was taken from the kettle five minutes later, specific gravity 1.04 is equivalent to 24 degrees under the same conditions. He now has established a relation between the degrees on his hydrometer and the actual specific gravity. (The reason for putting the pulp through a finisher before determining the specific gravity is that he wants to make this test under the same conditions that the buyer would make it.)

Now, if the packer decides that he wants to condense his season’s run of pulp to 1.035, he simply cooks it all to 18 degrees on his hydrometer, providing this is the comparison he got. Under his conditions he may find that 16 or 20 degrees equals specific gravity 1.035. As stated before, each packer must determine this for himself.

Method of Using Hydrometer

The cook should fill a tall gallon measure with the boiling pulp and allow the spindle to sink into it slowly. Do not drop it into the pulp so that it will fall suddenly, as the weight of the mercury or shot in the bottom will carry it farther than it should go. It will be noticed that the spindle will sink rapidly for a few seconds and then almost come to a standstill. At this point—when a standstill is almost reached—the reading should be taken. It requires quite a little time to reach an absolute standstill, and this is not necessary, as it is easy, with a little practice, to catch the other point and take the reading. After the reading is taken, lift out the spindle, stir the pulp with it, and allow it to sink again as a check determination, merely for the satisfaction of being doubly sure. You will find that you get the same reading unless you wait so long before making the check determination that the sample has had a chance to cool considerably. As the test only takes ten seconds, the two tests can be made in a half minute at the most, which gives the pulp no chance to cool.

The hydrometer method is not absolutely fool proof, but it is as near fool proof as anything I know of. Neither is it the acme of perfection in a pulp testing method, but it is, in my opinion, far better than anything that has been suggested to date. It is simple, and accurate enough for all practical purposes, and any ordinary laborer can be shown in a few minutes how to make the test, and the chances of error are very small indeed.

This method will not work where crushed tomatoes are being condensed. It is necessary that the tomato juice be previously cycloned. The pulp must be homogeneous and not lumpy and full of skins to be capable of being tested by the direct hydrometer method. When determining the finishing point on crushed tomatoes it is best to use either the eye or the specific gravity test by weighing.

Finishing the Cooking

The steam should be kept on the kettle continuously until the batch is done. While testing is being done it is not necessary to shut off the steam. If salt is used it should be scattered over the batch slowly a few minutes before it is done. Salt increases the specific gravity, and also the hydrometer reading. The relation between the hydrometer reading and the specific gravity can be worked out just as well where salt is used as when it is not used.

The addition of salt does add to the flavor, and some buyers prefer it, while others do not. I have seen buyers pick out a poor quality pulp with salt in it in preference to a much better quality with no salt.

As soon as the steam valve is closed the exhaust should be opened to discharge the steam from the coil or jacket and allow it to cool as quickly as possible.

It is often necessary to hold batches in the cooking kettles for some time after the cooking is finished. This darkens the pulp some, both because of contact with the air, while hot, and from long contact with the sides of the kettle or coil, which remain hot. Cooked pulp should therefore be discharged from the kettle just as soon as possible. If held over 30 minutes in the kettle it should be given a momentary boil before letting it down. Be careful to avoid contamination in the kettle after the steam is shut off, such as cold dirty water dripping in from rafters overhead, and leaks from pipes over the kettles through which cold tomato juice is flowing. Such material will not become sterilized merely by contact with the hot pulp, and may cause swells in the canned product if there is very much of it.

CHAPTER V
CONVEYING THE CONDENSED, STRAINED, OR CRUSHED TOMATOES TO THE FINISHING MACHINE AND FINISHING SAME

Conveying to Finisher

The fewer pipes and receiving tanks the condensed pulp passes through before being filled in the cans, the better. All of this conveying and finishing equipment offers possibilities of contamination, and allows the cooked pulp to cool to some extent before it is filled. Eliminate as much equipment as possible between the cooking kettle and the filler, and have the pulp enter the cans at at least 170 degrees F., and if possible, at 180 degrees or above. A receiving tank between the cooking kettles and the filler should be dispensed with if possible, and the finishing machine draw the cooked pulp direct from the kettle by means of a short line of enamel lined pipe.

Receiving Tanks

Unfortunately the arrangement of many plants is such that it is almost necessary to use a receiving tank; at least in such cases it would be a disadvantage not to have one. Where a tank must be used here it should be in such a position that it is easily accessible, so that it will not be necessary for a man to be an acrobat to get into it, inspect it, and see that it is kept clean, and that an inch of pulp is not allowed to lie in it and get cold while waiting for another batch to come down.

The best kind of a tank for this purpose is an enamel or glass-lined tank with a rounded, tapering bottom so that it will almost drain itself completely, and what little adheres to the sides can be scraped down in a few seconds if it is necessary to wait five or ten minutes for a fresh, hot batch to come down. Even if it isn’t scraped at all it will probably not cause any trouble in a tank like this. Wooden tanks will do, of course, but it would pay a packer who must use a tank here to throw out his wooden one and put in a tank such as is recommended above. It is hard to construct a wooden tank so that it will drain well; in fact, nine out of ten scarcely drain themselves at all; they are never kept as clean as they should be, and wet wood seems to be a favorite spot for molds to grow, so that frequent scrubbing is necessary if it is kept sanitary. It is most important to inspect the receiving tank carefully before it is first used in the morning, as they sometimes mold slightly over night, or dirt falls into them from overhead. A steam hose should be kept close to a wooden tank to sterilize it at night after it is scrubbed out.

Finishing

Whether or not a receiving tank is used, the finishing machine should be as close to the cooking kettles as possible, and should receive constant attention from a careful operator who can comprehend to some degree the importance of keeping it clean. If the filling department gets ahead of the cooking department and is obliged to wait fifteen minutes or a half hour for a fresh batch of pulp to come down, the man who tends to the finisher should take it apart at once, wash it off, steam it off thoroughly with the steam hose, and put it together again so that it will be clean and practically sterile when it receives the next batch. Otherwise the screen and the brushes will be clogged up with cold pulp when the fresh batch comes down, which is a bad condition, especially if the pulp is not to be sterilized after it is filled, which is usually the case with 5–gal. pulp. Even though the finisher is operated continuously through the day, it should be taken apart and cleaned at least twice during the morning and twice during the afternoon.

The finishing machine should be operated slowly, so that the pumice will come out dry. The small receiving box under the finisher should drain completely so that it does not have a foot of cold pulp lying in it when the finisher is idle.

Screen Metal for Finisher

The best kind of screen for the finisher is made of monel metal. The brass screen is more common; however, the same thing can be had in monel metal, and it does not offer the opportunity for metallic contamination that the brass screen does. The monel metal screens wear very well and have proven themselves to be satisfactory in every respect. Aluminum should not be used, as it is eaten up by the tomato acid and will not last long.

Effect of Finishing on Mold Count

The opinion has often been expressed that the brushing of the pulp through the fine meshes of the screen breaks up the small clumps of mold and scatters them in small threads throughout the mass, thus increasing the mold count, since this count is not based on the total quantity of mold present, but upon the number of microscopic fields containing molds. Thus, by scattering the mold, instead of allowing it to be retained in comparatively large clumps, the number of microscopic fields containing mold threads would be increased.

Although one might reasonably expect this to take place, experiments have proven that it does not take place. Several years ago, in order to determine this point, I analyzed thirty batches of catsup just before entering the finisher and again just after coming through the finisher. In every case the percentage of microscopic fields containing molds after finishing was practically the same as before finishing. A cone-shaped finisher with three revolving brushes and fine mesh screen was used for this test.

Finishing Before Cooking

Although the finishing machine, if properly tended to, is probably responsible for very little of the spoilage in pulp, it has been suggested to use the finisher before the pulp is condensed. Then the pulp can be drawn direct from the kettle to the cans, and the chance of contamination and cooling in the finisher can be eliminated. This idea is well worth experimenting with, as the pulp could be filled at almost the boiling point. I have not tried out this idea, but offer it here as a possibility which has advantages which are well worth looking into. Packers who are having spoilage trouble which they cannot attribute to other causes would do well to experiment with it. As to whether both the pulp machine and finisher would have to be used before the cooking, or whether the finisher alone would do, providing the tomatoes were previously crushed, or cooked in a “breaking tank,” would have to be determined by experiment. The method may be in use now by some packers; however, I have not heard of it being used.

CHAPTER VI
FILLING THE FINISHED PULP AND STORING THE CANNED PRODUCT

Filling Devices for Five Gallons

The most commonly used containers for pulp are the five-gallon can, the No. 10 and the No. 1 can.

The usual method of filling 5–gal. cans is to draw the pulp from the finishing machine by means of a large, heavy wall, single line hose filling one can at a time. Some packers use a manifold by which five cans can be filled at once. This requires a lot of valves and enamel lined pipe fittings, and unless the operator is very expert the manifold will not do the work any faster than a single line hose.

Square Can and Round Can

The square 5–gal. can is preferred by nearly all packers to the round can. The round can is hard to handle, hard to stack, and is very wasteful of space wherever it is stacked. The square can is to be preferred in every way.

Testing for Leaks

When new cans are being used it shouldn’t be taken for granted that they are absolutely free from leaks, as it is sometimes found that a large percentage of a car of cans will run bad, and the packer should test representative samples from the car as soon as it is received, so that he can reject it and secure other cans if the car doesn’t test up right. The best way to do this testing is with a small tank of water, a one-eighth inch air line, giving about four pounds pressure, and a can tester. A simple kind of can tester can be easily constructed in any blacksmith shop, and merely consists of an iron brace to fit around the can and which can be quickly tightened over the can and released, and a soft rubber semi-circle to fit tightly into the cap hole and which is gripped at the top and held in place by one side of the brace. The one-eighth inch brass air pipe passes through the center of the rubber semi-circle and into the can. As soon as the can is tightly clamped and the cap hole sealed by the rubber, the air is turned on and the can is immersed in the water. The leaks show up very quickly under a four-pound pressure, and a dozen cans can be tested in as many minutes.

Washing and Steaming

New cans, as well as old ones, should be thoroughly washed and steamed before filling. There is often a fine, light colored dust in new cans which a good strong spray of water properly directed into the inverted cans will remove. Through the same pipe which directs the spray of water into the cans, the cans can be steamed by means of a simple arrangement of valves on the steam and water pipes. A washing and steaming rack can easily be fitted up which will wash and steam a half dozen cans at once. A single stream of water entering the cap hole of the inverted can is not sufficient to clean it. The pipe which enters the cap hole should be capped, and about three holes drilled into this cap at a slight slant so that the upward spray of water will strike three different spots in the bottom of the inverted can, and make the washing thorough.

If the average packer could see just how little of the inside surface of his 5–gal. cans is actually washed, he would be surprised. About fifteen seconds is sufficient time to spray the inside of the cans, and then the water valve can be closed and the steam valve turned on. The steam should be kept on for a full minute and kept on strong. The idea is not merely to heat the can but to sterilize it, at least to some degree, before the pulp is admitted. The average employee steaming 5–gal. cans leaves the steam on ten seconds at the most, and often not more than three seconds. Such a short steaming does very little good. The space of time between the steaming and filling should be just as short as possible. The employees should not be permitted to keep a half dozen cans steamed ahead all the time so that they are cold by the time the pulp enters them.

Filling and Capping

As stated in the previous chapter, the temperature of the pulp when it is filled should be at least 170 degrees F. and preferably above 180 degrees. The cans should be filled clear to the top with the pipe or hose which conducts the hot pulp from the finisher; they should not be topped off out of a dipper which contains luke warm pulp and is used for topping purposes. It is not necessary to do this topping and the practice should not be permitted. The sponges which are used for wiping the edges of the cap hole should be kept in a bucket of clean, hot water, and put back in the bucket after being used on a truckload of cans. The capping and tipping job should undergo inspection before the cans are trucked away.

Handling Filled Cans

Cans of filled pulp should be handled carefully. The cans should be set down easily, so as to strain the seams as little as possible. Of course the laborer wants to let go of cans of red-hot pulp just as quickly as possible, but it is not necessary to drop them several inches, and the employees should be taught to set the can on edge and then let its weight straighten it up. If the employee is given good thick gloves it is just as easy to handle the cans carefully. I had occasion at one time to check up on the percentage of swells resulting from one pile of pulp which was stacked by an old hand who knew how to handle pulp easily and carefully, and another pile from the same day’s run which was stacked by a gang of new and uninstructed help who simply picked the cans off the truck and dropped them in place. These were second-hand cans, and the difference was considerable.

Both filled cans and empty cans should be handled almost like eggs. One large pulp packing concern is particularly cautious about this, and it is certainly soothing to the nerves to see their employees handling 5–gal. cans after witnessing the rough and tumble methods in the average plant. They know that it pays to be particular, and that they can get three years’ use out of almost all of their 135–lb. plate cans, and not have many swells either. This concern rarely sells any of their pulp, but puts it up for their own use, to be made into bean sauce, catsup, soup, etc., during the winter months.

Advantages of Separating Batches

Some packers stack their pulp away without dating it; others date each day’s run; while others stack each batch separately. The latter system is practicable where the pulp is cooked in large batches of about 300 gallons or more and in working up the pulp during the winter months it is a great help. For instance, suppose part of the pulp is to be used for catsup and part for bean sauce. The packer can take batches one to fifty, for example, open one can from each batch, examine it for color and microscopical analysis and he knows exactly what he has in that stack of pulp, which may be three thousand cans. He can select the various batches to be used for the purpose to which they are best adapted, and he can be absolutely sure that each can in a batch is exactly the same in every respect.

Take another example: We will say that the packer is selling his pulp. His records show that on September 20th and on October 2nd, for instance, he had a lot of bad tomatoes; shipments received on those days were unavoidably held up and he had to make the best of the situation. He knows, however, that on those same dates he had a lot of good tomatoes which came in by wagon haul and that they were run up at the same time. He has a large order for pulp from a catsup maker who is very particular about the microscopical analysis of the goods he buys. In order to play absolutely safe, the packer can take a sample from each batch of the pulp run on September 20th and October 2nd, and if a half dozen batches run too high he can omit them when he makes the shipment to this buyer. If he preserved a sample from each batch run on these dates at the time they were run, which is the better way, it makes the sorting out of this pulp a very easy matter. He thus eliminates the danger of the loss of a good buyer by sending him even a comparatively small quantity of pulp which is high in micro-organisms.

It may seem to one who has never tried it that stacking each batch of pulp separately would involve an awful lot of extra labor, and loss of valuable space when stacking. As a matter of fact, it involves no extra labor at all and no extra space. I have had a season’s pack of pulp amounting to 75,000 5–gal. cans at one plant and cooked in batches of 300 gallons each, stacked each batch separate and it was no trouble at all. The inspector who examined the tipping and capping job, or the tipper, if the inspecting was done by him, merely took a fine stiff brush and a marking pot and marked the batch number on the cap of each can. This only takes a half minute for a truck load. The date was not marked on the can, as a record of the batch numbers run on each date during the season was kept at the office. When the pulp was piled away each batch was stacked together, and where one batch left off and another one began a slip of wood was inserted between two of the cans.

On days when the tomatoes are running bad, or there is a scarcity of help for the sorting belt, it is wise to preserve a sample from each batch and have an analysis made of it for reference when the pulp is shipped out. On days when a good grade of tomatoes are being run it is hardly necessary to analyze every batch, but a sample of about every third batch can be taken.

Stacking each day’s run separate is, of course, better than no separation at all. However, there are not many days when the entire run will have a similar analysis; the best becomes inseparably mixed up with the worst, and when the pulp is worked up the packer is working in the dark. To stack a season’s run away without any system of separating various divisions of it is the worst kind of folly, and is almost sure to lead to trouble.

How to Stack

When the pulp is stacked away a space of at least an inch should be left between each can to allow the air to circulate and prevent stack burning. If this is not done, a pile of pulp may hold the heat for a week or ten days, and the pulp, particularly that on the inside, will become brown or even black, due to the long exposure to the heat. The quicker the pulp can be cooled, the more the bright red color of the tomato will be retained.

The height to which the pulp is stacked depends upon the heaviness of the plate of which the can is made, and also, of course, upon the weight the floor of the warehouse is able to stand. As a rule it is not wise to pack 5–gal. cans of 107–lb. plate over four high, and not over five high for cans of 135–lb. plate. Dry, sheltered storage should be provided for pulp, and it will be found to pay in the end. Exposure to the elements is very hard on the cans, and alternate freezing and thawing of the pulp is a great strain on the seams of the can. A comparison of the leaks and swells on pulp stored in shelter, and that stored in the open, will convince the packer that it pays to construct dry storage space.

Narrow aisleways should be provided for between the stacked pulp so that it can be frequently inspected for leaks and swells. By pulling out a leaker in time, several other cans are prevented from becoming leakers, as the leaking pulp from one can will run down on several others, and the pulp, in connection with the oxygen of the air, will eat through the tin plate, causing rust spots, and then pin holes. Frequent inspection of the pulp pile and pulling out cans when they are just beginning to leak or swell will save the packer a lot of money.

Cans should not be stacked on thin boards which will leave the surface of the can close to the ground, as the moisture of the ground will quickly rust the tin. It almost seems foolish to mention such a point, but much pulp is stacked this way and the entire bottom layer when turned up will be moldy and rusty on one side. The surface of the can should be at least two inches from the ground. Lacquering will help some, but will not prevent rusting if the cans are close to the ground.

Processing

Nothing has up to this point been said about the processing of 5–gal. pulp. Very few packers process their pulp, and many unprocessed packs have been put up that have not shown over 1 per cent of leaks and swells where new cans were used and the various manufacturing processes were carried out as they should be. In many cases a long shipment of such pulp, after having been stored in a sheltered place for several months, has produced very few additional swells.

One large packer of pulp has for years given his 5–gal. cans a 30–minute process in boiling water, having them pass slowly through a boiling water bath on a chain carrier, the speed of which is regulated so as to give each can the required time in bath. The cans are placed on the chain as soon as they are capped and tipped. Although this packer is very careful in his manufacturing methods he processes as a matter of insurance, principally because a great deal of his pulp is shipped long distances. He must figure that it pays him or he wouldn’t keep it up, as the processing involves quite a little extra handling and extra equipment, and of course has a tendency to darken the pulp somewhat.

Thirty minutes at boiling temperature is, of course, not sufficient time to bring the center of the can near the boiling point, but it will sterilize the can itself and that portion of the pulp which is near the outside. If the pulp is filled very hot, that portion of it which is in the center of the can, being the last to cool, should practically sterilize itself.

Life of Cans

Where a packer puts up pulp in 5–gal. cans for his own use during the winter months he ought to be able to get two years’ use out of all of his cans, and three years out of a large percentage of them. It is questionable whether it is ever advisable to use a can over three seasons. One reaches a point where the percentage of swells is so large with old cans that the saving of the cans is unprofitable. When a new can is first used, the year should be indelibly stamped on the can, so that at any time the packer can go through his stock of used cans and tell how many seasons’ use each can has had. This will prove a help in making a decision on which cans are worth holding over for another season, and which ones are not. It also gives him a line on the kind of can that gives him the most value for his money.

Enamel lined cans are now being used a great deal, and as a rule they seem to give a little better service than the plain tin, although this is not always the case. Some packers think the enamel imparts a very slight foreign taste to the pulp, but I have never been able to detect it. Enameling or lacquering of the outside of the cans is essential if there is not sufficient sheltered storage for the pulp, or if it must be stacked in a damp warehouse. An excessive amount of moisture in the air will quickly start the tin to rusting on plain cans, and many cannery warerooms are entirely too moist for stacking cans, as they are near the process room, and the air is often misty with the presence of condensing steam from the process tanks. If there is ample dry storage space, the outside enameling of the cans does not seem to be an advantage.

Washing and Drying Cans

When the season’s pack of pulp is being worked up, the cans which are to be saved for another season’s use should be thoroughly washed out in a tub with hot water. Spraying devices will not work, as the top of the can will probably have a layer of pulp stuck to it, due to the receding of the pulp in the can when it cooled, and even a heavy spray will not remove all of this. The cans must be partially filled with hot water and shaken hard to properly clean them. The foreman should inspect the washed cans at frequent intervals by means of a small electric light which is wired to a short rod and which can easily be inserted in the can through the cap hole. If the washing is not thoroughly done this will show it up quickly.

After as much of the water as possible is shaken out of the cans they should be put in a drying oven and left over night. In the morning the cans should be thoroughly dry if sufficient steam is kept in the oven radiators. The oven is made with a partition which divides it into two parts, and one part can be filled with the wet cans while the other side is being emptied of the dry cans.

Protection From Dust

After the cans are dried, a pasteboard insert should be placed in the cap holes to keep the dust out of them while they are in storage during the winter and spring. One of the can companies at least, supplies these pasteboard inserts or inverted caps with their cans, and they fit snugly into the cap hole.

Testing Used Cans

Before the old cans are used the following year they should all be tested for pin hole leaks and the leaks patched up. They should then be re-tested and not used until they are shown to be tight under air pressure when immersed in water. This can be done during the spring and summer months, and the packer can then be reasonably sure that his old cans are in good shape for the next season’s run. If the cans are very old and the seams are very rusty, new pin holes will be opened up every time air pressure is put in them. Such cans should, of course, be thrown away.

Packing 10’s and 1’s

Pulp packed in No. 10 and No. 1 cans is usually filled with a rotary filling machine, although No. 10’s are often filled from a single line pipe and the filling can be done quite rapidly where the operator is expert at the job. If it is necessary to top any of the cans, it should be done from a small jacketed kettle which is connected up near the filler, so that the pulp used for topping can be kept hot. The cans should be put through a can washer and steamer before filling.

No. 1 pulp should have a much larger call from the consumer than it has, and it could be made very popular if a high standard of quality was set and maintained, and the advantage of its use advertised to the housewife. Many consumers who have purchased the small size pulp or puree for use in making tomato sauce, spaghetti, tomato soup, etc., have been disappointed in the quality, and after one trial have gone back to canned tomatoes for these purposes.

For No. 10’s a process in boiling water of 40 minutes in the old style straight process tank is usually considered sufficient; this is to be followed by a very gradual cooling in water so that the cans will not buckle badly. For the No. 1 size a 20–minute process in boiling water is sufficient. It is always well to cool the cans about ten minutes so they will not retain the heat a great length of time. A better color and flavor can be maintained if the goods are cooled in water after processing. If a continuous agitating cooker is used for processing the lengths of time given above can be cut down at least 60 per cent.

Packing Barrel Pulp

Barrel pulp is scarcely being packed any more, as the barrel has shown itself to be unfit for pulp which is packed without preservative. The use of barrels today is usually only resorted to in emergency cases when cans for the purpose are not available. If the pulp is to undergo long storage and shipment, or any great amount of handling, barrel goods will usually show quite a big loss, not only because much of the pulp is spoiled so that the spoilage is evident at once upon inspection, but because of the growth of yeasts and bacteria in the pulp while it has been in storage, and because of loss of color due to the action of air seeping into the barrel. Wooden barrels as a rule are not absolutely air tight, and it is hard to make them so.

I have packed pulp in good uncharred whisky barrels, using 5 lbs. of salt to the barrel, and rolled the barrels to a sheltered place where they would not be disturbed until they were ready to open, and after two or three months’ storage the pulp was all right. If this pulp had been moved, or held until a spell of warm weather came on, it is doubtful if it would have shown up so well. The barrels should be washed out well and steamed for about five minutes before being filled, and the bungs should be burlapped.

Metal Drums

Ingot iron drums, such as are used for shipping oil, have been recommended for tomato pulp and I have tried them, but they will not do, as the tomato acid dissolves too much of the iron.

A Method of Preserving Pulp in Barrels

As a method of preserving pulp in barrels one packer for a number of years put hydrochloric acid in it. This, being a strong acid, is also quite a good preservative, and evidently kept the pulp in good shape. When the pulp was worked up, enough bicarbonate of soda was added to neutralize this acid, and the result of the neutralization was sodium chloride, or common salt. There evidently could be no objection made to this from a pure food standpoint, as none of the acid was left in the pulp after the neutralization, and sodium chloride is a common ingredient of pulp. However, the process darkened the pulp, which was an objection. As to whether or not the flavor was impaired by this treatment I do not know.

CHAPTER VII
THE MICRO-ORGANISMS OF TOMATO PRODUCTS; THE ATTITUDE OF THE PURE FOOD AUTHORITIES TOWARD THEM; AND THE INTERPRETATION OF ANALYSES

Micro-Organisms; What They Are

By micro-organisms we mean molds, yeasts, bacteria, and their spores. The term “micro-organisms” takes in all of these.

This chapter will deal with the subject in as short and concise a manner as possible, with the object of giving the manufacturer a working knowledge of it that will help him in his everyday factory routine. Although volumes have been written about micro-organisms in food, it is not necessary for the packer of tomato products to have an accurate, detailed scientific knowledge of the subject in all its ramifications, but a general understanding of it will suffice for practically all purposes.

What are molds, yeasts, spores, and bacteria? Are they animals or plants? Where do they grow, and under what conditions do they multiply most rapidly? Are they harmful, or are the kinds found in tomatoes all harmless varieties? If they are harmless, why does the government object to them? Why is a product containing a certain number considered all right, while when a larger number is present the product is said by the government to consist in whole or in part of a filthy, decomposed, putrid vegetable substance? Aren’t such foods as Roquefort cheese, cottage cheese, buttermilk, and sauerkraut fairly swarming with the same kinds of germs as tomato pulp? Aren’t these foods all considered healthful? Then why object to these germs in tomato pulp? Aren’t the germs all killed by the boiling, anyway? These are questions often asked by pulp packers, and it is hoped that the following will throw some light on the subject.

Molds, yeasts, spores, and bacteria are very tiny plants, not animals. They are so small that they can only be seen by the naked eye when there are very large masses of them together, consisting, in the case of bacteria and yeasts, of hundreds of millions of small individual plants, and in the case of molds, of many individual mold plants closely massed together.

You have all seen large tufts of white mold on tomatoes, and black mold covering a loaf of bread, but you probably did not realize the enormous numbers of individual mold plants that were present, or the rapidity with which they multiplied themselves. You have all seen swelled cans of tomato pulp, and after the cans were opened you have noticed the bubbles rising in the pulp, and have noted the very sour taste and often an extremely disagreeable odor. In every thimbleful of that sour pulp there were hundreds of millions of bacteria and yeast cells, so small in size that many thousand could collect at the same time on the point of a pin and they would not be noticed by the naked eye. It was these tiny bacteria and yeast plants which caused the physical and chemical changes in that pulp. Just as a parasitic vine winds itself around a tree and sucks the life out of it, so these millions of bacteria and yeast plants sucked all the goodness out of this tomato pulp, and left nothing but sour, decomposed tomato fiber, acid, and foul-smelling gas.

Molds

The structure of the mold plant is similar to that of a very small vine, the branches of which are many and are closely massed together. The tiny threads or filaments of mold resemble the vine and its branches. These threads keep sending out new shoots which spread rapidly all over the surface the mold is growing on, and the fruit of the mold plant, which is called spores, is similar to the little berries which grow at the ends of the branches of a vine. These berries are the fruit of the vine; spores are the fruit of the mold plant. Just as the berries contain seeds which reproduce the plant, so the tiny spores contain the seed which will reproduce the mold plant. These spores grow at the end of the mold threads or branches, and when ripe, either fall on the surface directly beneath, or are carried away by a breath of air and move along with the dust.

The spores of the mold plant will remain alive for months in a dry state, floating in the air, or if the air be very still, falling to the surface. The air everywhere is full of them, and as soon as they light upon a moist surface, such as tomato juice, for example, which contains nourishment for them, they begin to send out shoots of mold threads and reproduce another mold plant.

Fig. 4.—Mold filament from catsup. (×150.)

Mold grows most rapidly upon a warm surface, preferably about the temperature of the human body. It will not grow on a surface which is at freezing temperature, or on a very hot surface. Under these extremes of temperature it is unable to multiply itself. Boiling kills the mold plant, and continued boiling of 15 minutes or more also kills the seeds or spores of practically all species. That is one reason why it is desirable to bring peeled tomatoes or tomato juice to a boil as soon as possible—so that the mold and mold spores which are always on these surfaces will be killed before they have an opportunity to grow.

There are many different species or varieties of mold plants which thrive on tomatoes and tomato pulp, but they are all very similar; they reproduce themselves in exactly the same way, and they are all arrested in their growth by extremes of temperature, and are killed by continued boiling. It should not be thought, however, that boiling for a very few minutes will kill all mold spores, as they have a tough surface which has considerable resistance to heat. I have seen 5–gal. pulp packed which was only given a very short boil on account of low steam pressure, and molds grew in the sealed cans after packing to such an extent that the pulp all had to be thrown away. It is safe to assume, however, that a 15–minute boil will kill mold spores and prevent the growth of molds in the cans after they are sealed, providing, of course, that the pulp is filled hot into cans which are clean and almost sterile.

Bacteria

Bacteria and yeasts are very much smaller plants than molds. While an individual mold plant, growing as stated above like a very small vine, branches out and spreads over considerable surface, bacteria (that is, those forms in which the pulp packer is interested) are very short, single rods, which, when multiplied in size 500 times by the microscope, appear to be from 1
32 to ⅛ of an inch long. Yeasts, when multiplied in size 500 times, usually appear to be from two to five times as large as a pin head.

The rod-shaped bacteria referred to above are mainly the lactic acid, and acetic acid bacteria, both of which produce fermentation in tomato products. The lactic acid germ is the same one which causes milk to sour, while the acetic acid germ is the one which produces the acetic acid of vinegar. There are many other kinds of bacteria in tomato pulp, many of which are small, round cells. However, the bulk of these probably come from the soil and are natural to the tomato, and are not counted when the number of bacteria per cubic centimeter are estimated. The rod-shaped types indicate fermentation.

Fig. 5.—Rod-shaped bacteria from tomato pulp, common in bad catsups. (×500.)

Bacteria reproduce themselves with amazing rapidity. It has been found out by watching them multiply under the microscope that under favorable conditions one germ reproduces itself every 30 minutes, and in some cases reproduction is known to have been even more rapid than that. The method of reproduction is by simple division. The rod-shaped bacterium is just like a match in shape, only many thousand times smaller, and in the space of about 30 minutes it will divide itself in the middle, thus changing itself into two shorter rods. Each of these rods grows in length, and each of them then divides, making four rods. In 30 minutes more the four rods change into eight, etc. It is the simplest method of reproduction there is.

Bacteria also have another method of reproducing themselves which they resort to when conditions become unfavorable for their growth and they can no longer multiply themselves by the simple division method. Such an unfavorable condition would be the drying up of the moist surface on which they are growing. In this case the rod-shaped bacterium forms one or more spores within itself. These bacteria spores are somewhat similar to mold spores, but are much smaller. However, they are only produced by bacteria under unfavorable conditions, while the mold plant produces them under all conditions. The bacteria spores, like mold spores, have a tough surface which gives them high resistance, and they contain the germ of bacteria life which can reproduce the species when favorable conditions for growth are again encountered. The bacteria spores, therefore, float through the air as do the mold spores, remaining in the dry state without nourishment for months at a time, and as soon as they light upon a moist surface containing the elements for growth, even to a very small degree, they reproduce the rod-shaped bacteria form, which begins to multiply itself again by the simple division method.

Although most bacteria spores are killed by boiling for 10 or 15 minutes, there are a few species of extremely high resistance which have been known to remain alive after several hours’ boiling. Spores of this nature are infrequent, however, and the packer might as well forget that they exist. Not one case of spoilage out of a hundred is caused by the presence of such spores, and if all food products were cooked a length of time sufficient to kill all bacteria spores which might possibly be present, the foods would be cooked to death, and unfit to eat.

Yeasts

Yeasts are very tiny individual cells, and multiply by budding, instead of by simple division, as bacteria do. Instead of the yeast cell dividing in half, thus producing two cells, it remains intact, but a bud forms on its outer surface. This bud grows in size until it becomes almost as large as the cell which produced it, and then it separates from the mother cell, and we have two yeast cells. Each of these two cells then produces buds, which again separate, and so on. Like bacteria, the multiplication is very rapid under favorable conditions. Favorable conditions for yeasts and bacteria are the same as they are for mold, that is, a warm temperature, preferably near blood heat, and a moist substance which is not too strongly acid, and which contains the elements necessary for growth, preferably the natural sugar of fruits and vegetables.

Fig. 6.—Yeasts and spherical bacteria from decaying tomatoes. (× 500.) [The oval bodies are the yeasts, some in budding stage; the bacteria appear as small spheres, or pairs of spheres.]

Yeasts are the principal gas-forming agents in the fermentation of pulp. In the production of this gas they consume the natural sugar of the tomato. They will multiply by the budding method described above as long as they are in a medium which is favorable for their growth. As soon as this medium drys up, or for some other reason becomes an unfavorable medium for the multiplication of the yeast cells, the yeasts resort to spore forming, just as bacteria do. These spores are formed within the yeast cell, and when the cell wall breaks the spores pass off into the air. Like all other spores, they have a high resistance, and will float around in the dry state and remain alive for a very long time. When they light upon a medium in which they can grow they reproduce the yeast species, in the same manner in which the bacteria spore reproduces the bacteria species from which it was derived.

Spores

The spores, then, which are found in tomato products are of three different kinds, namely, mold spores, yeast spores, and bacteria spores. The greater number are almost always mold spores, since the mold plant produces spores under all conditions, while yeasts and bacteria only produce them under unfavorable conditions. When microscopical analyses of tomato products are reported, the mold spores and yeast spores are included with the yeasts in the term “Yeasts and Spores.” This is because a large number of the spores are very similar to yeast cells in appearance, and as it would be a laborious process for the analyst to separate them, the yeasts and spores are included in one figure, which greatly simplifies the analysis. The bacteria spores are not included in the count of “Yeasts and Spores.”

How Germs Retard Their Own Growth