T NO TIME in history has the co~iservna,tionof food, ~ s ~ e perishable c ~ ~ ~ food, ~ ybeen of greater importance than in this Work! W'ar KormiLilp, we in the United tatera would depend upon canning, dehydrating, and freesinp, he5 weYI 8.8 on salt^^^^ e u r i i ~ gand ~ smoking. Refrigerated railway ear8 and motor trucks and steamdlips wolaEd traxrspart &becooled wr Iromn p r d u ~ to t ~the desired destination where, nine tarnee out, of ten. a, refrigerated rvarehoinse would wait them. Our Ainorieaii dmax y, rapi&y expanoing in sadity and warjety as vitarnina, cdciurn wits, phospkasrotBinS, ete., have become holisPhold words, has been held in jam, ems, locker freewxs, wad bine in tvhutevsx form most appealed KO the prospective 6on811mer. Food conser-aa%aopn $88 been based on the saving of a normal surplus production, on an w e n ciistribution of seasonal pro4hc.ts throughout the years and a leveling of priees---all from the viewpoint of American requirements and preferences. Now under the candieions of total WhP, with om soldiers on the shosea Qf the HeVC?%l8884and OUT saiitrrs O l i their WatPW, &hie problem becomes enIB1LireIy dl%Tent>* in Rdditlii)X1 to fee our troops abroad and at home, wo lTb115t, fssd our 8 They are! far flung. China needs mal& far i t 4 mothcrleas children. Russia needs fats for its people in the north, e Britain needs a wide variety OB fsodsinffs. 8'471-ren the gtop firing E11d the r e s h i n t s of z3,Cti"Y.e W B P are soanewhat ved from the people of conquered matioras, the cay for. food, food, anid lllORe food aslklst be h W d d prOl3Ipt%yn The r e ~ ~ small & ~~rnouait ~ e ~of ~mctd svsiisbk for cam m1ase be held far 5aappliea $0 the Army, Nayy, Merchant Marine, and Our swl%ia8psuch ns ovayorated mnlk and meat productL3, Ha suig, 1942, Lcad-Lease purchases of frozen pork amounted to Borne pwmds, but casmeli pork over ~~~~~~~~~0~ pounds mrerew l ~ be i ~ r ~ ~ t ~ c ~ ~ ~ y no cam fop. civi!isns. Our youa food-dehyd%tlng Industry, t%ioughgrowing by lenps and h i n d s , as yet. falls far short of the quantities of vegetables 1 equircd for over5ea 1mo. C i v h m needs everywhere are ~ Q W secondary to those of the armed farces. Civilian needs here in ameslas must be satisfied with what food i s available. Tbanka: to starting the upwilrd push of production more! than two years ago, we are Bikely t o have enough for & d i m nee& (not Imaarios)! provided we comeme ~~~~~~~~~
a
January, 1943
INDUSTRIAL A N D ENGINEERING CHEMISTRY
space, we now turn the figures around. Officials in Washington, making plans and solving problems concerning refrigerated space, expected that by October, 1942, the freezers of the country would have over 1,257,000,000 pounds of pork, fruits, vegetables, butter, and frozen eggs, to be further increased in December by over 300,000,000 pounds of poultry and meats. We now have 9,600,000 cases of eggs in cooler space. Much of this tonnage is en route to steamers to be shipped Lend-Lease or to our own bases outside the continental United States, and only waits in warehouses for sailings. Even so, occupancy now of cold storage warehouses is reported over 70 per cent, while packers and private facilities are a t 90 per cent or over. Hence, on all accounts, we are looking as never before a t the size of paokages and the saving of space. For example, one ton of carcass beef will occupy 135 cubic feet of space, be it hung or piled. Deboned and packed into cartons, it will occupy 36 cubic feet. A crate of fresh spinach, holding 41 pounds, occupies 2.8 cubic feet. Blanched and frozen, a package of spinach holding 40 pounds occupies 1.11 cubic feet. Space in cars and trucks, whether refrigerated or not, is a t a premium. Some products take less space frozen and weigh less than when canned. For example, a million pounds of peas frozen in 12-ounce cartons require 27,940 cubic feet of storage space, while in %pound cans they need 43,180 cubic feet. To move the frozen peas would require thirty-one carloads of 36,000 pounds minimum, The canned peas would need sixty-four carloads.
63
Courtesy, Refrigerating Engineering
Typical Cooler Room in a Locker Plant
cially appraising eye at the facts coming by the scientifia route. Two facts were outstanding-the enthusiastic reception by the householder of the mechanically operated refrigerator and the results as demonstrated by Birdseye of Quick freezing the quick freeze. When a hostess served quick frozen foods to her guests and told them how she could keep a supply in The refrigeration of perishables grew, as do so many the freezer compartment of her refrigerator, the food purAmerican projects, rather like Topsy. The cut-and-try veyor dared no longer malign frozen foods as “cold storage method could go just so far. In 1903 the United States stuff”, and the refrigerated warehouseman seriously set about Department of Agriculture sent its young scientific men to harmonizing the temperatures and conditions in his warestudy the conservation of peaches in Georgia; and in 1905 house with the findings coming from the laboratories. the department began its studies of conservation of poultry, The definition of “quick frozen” has undergone several eggs, and fish. Milk and butter were already receiving modifications since its use became general. As originally scientific attention. defined, it signified passing through the zone of water crystalIt was not until well into the twenties that the refrigerating lization-that is, from +31” to f23’ F.-in not more than industry in the United States began to look with a commer30 minutes. Crystals formed with such speed are extremely small. They are intracellular, and on thawing, the water is more readily absorbed by the cellular substance. Such speedy freezing was difficult, even for small packages. It was almost impossible, commercially speaking, for packages weighing 20 or 30 pounds such as are needed for institutional and quantity serving. Uniformly fine quality goods in packages of family size, on the one hand, and institutional size, on the other, were the goals to be obtained. One packer used a tunnel machine and put an acceptable product on the market. Another used low-temperature metal plates against his packages, and the contents froze satisfactorily. Another spread out his pack in a room running -25’ F. and kept the air circulating, and his product found favor in the sight of the customer, and so on. The classical researches of Plank (I) showing the percentage of water frozen out of meat a t different temperatures with a total freezing a t -67’ F. and some denaturing Courtesy, Refrigerating Enqfneering of the protein caused considerable scienFruit Stored in a Cold Storage Room tific consternation but not much practi-
cally. It mas too difficult to obtain such extremely low temperatures commercially, and time did not permit holding packages in the quick freezer for such lengthy periods. KOW,a dozen years since we discussed ‘by the hour the method of getting a 30-minute water crystnl freeze so that me might call the product “quick frozen”. w e h.ave adopted the term for any package of household or institutional size containing a food product hard frozcn in a form ready for cooking or serving. If the quality is consistently good, the consumer asks no questions about how long it took to freeze the contents. It is to refrigeration, particularly freezer preservation, that QUP’ civilian population, especially, must look for an even apportioning of perishable foods throughout the year, Fresh fruits and vegetables in season will be marketed in larger quantities since canners and jam and jelly makers must be restricted in the use of tin and sugar. So far we Rave had enough refrigerated cars and trucks to haul the fresh goods. Fortunafely, frozen goods can be held in fiber containers, provided they are moisture vapor resistant. Desiccation is a bitter foe of quality in refrigerated perishables. We put up approximately 40 per cent more quick frozen package goods in 1942 than in 1941. Some of it went to the Army where it has been tried and found useful for United States camps. Much more has gone to the Navy which, ~ i n c e1936, has put some 0” F.carrying spsee in all new ships and in those overhauled and refitted, and so can hold frozen foods successfully. Kest year the Army 1\41 want more quick frozen perishables, and civilians will have far fewer cans. The aim, therefore, is to double the 1942 quick frozen pack in 1943. Considerable planning must go into such a program. In the first place, not all varieties of vegetables and fruits will freeze successfully. Therefore, the farmers must) agree t o plant varieties of peas, beans, beets. and so on, which are suitable for freezing. The freezing facilities n o r available can be pushed to give a larger output, but’ they cannot double our preient plant capacyty, Relatively little new steel v;ould be required, considering the tonnage t o be oblained, but steel is steel and every pound counts. It is estimated that forty thousand grocery stores are selling frozen foods direct to consumers. The volume sold in I942 increased greatly over 1941, but the business they can do, using the cabinets t’hey now haye, could be much heavier. If their facilities slioultl give out’,ei’ery ice cream shop could be a d.istribution point for the dinner a s well as the dessert. There is a nery development in the ofling-namely, frozen cooked foods. Our old friend, pork and benne, banished from the easi bj. the exigencies of ~vai’, now appears frozen in a paper carton. It is oiily a question of time until spaghetti i n
tomato sauce, corned beef hash, and other stand-bys fail back upon quick freezing and papal containers. I,ocker plants
A development of significance, especially in view of e food conservation during the wnr, is the frozen food l o c i s e ~ plant. Here in Large roomb, held at, 0” F~ v?: belciw~ ~tlpc: lockers, generally built of steel in the form of stacks of drawers, five high, each having a capmity af about 6 cubic feet. Each locker Id fronr 1% to 250 porxrd.s of meat or fruits or vego There are now rmre than 4500 locker p%mtsin this cou~itry,in which the owner of the goods has direct access Lo his Frozen prcduce. There is an average of 350 lockera per plant, which BlleanB that a million and a half farm families caw conserve food by locker freezing. Assuming five persons to E family gives a total of nearly 8,000,000 people who m s y be so fed. Usually the locker plant also provides facilities for cocahg and ripening meat, cutting carcasses, and wrapping in household. size packages, B rProrkroorn where fruits and vegetables are prepared and packaged for freezing, and o. sharp freezer where the initiai freeaing is done. The fronen goods arc: then transferred to the eustomer’g locker, to be removed as he desires. Many an ice making pla~ithas conwerted some ob its ice holding space into locker rooms, and many a cold storage marehouse has diversificc! its business by adding iocbers. Locker plants began as a convel.iience for the rural population. Kow urban populations, especially of t h e hanailer cities of the Ni’d‘dlavest,have a,Xso adopted this method of con-, serving perishables. In 1941.&he4,onnage so held was estimated at more than 50O,OOB,OBO pounds. With the pr scarcity of tin for cans and of all metals suitabie: for t o jars and of rubber for closures, it is probable that, we will see a big increase in the quantity of civilian food stjorod ir, lreker plants.
January, 1943
INDUSTRIAL AND ENGINEERING CHEMISTRY
65
locker conditions, and muchvaluableinformation has resulted. The conclusions are that vegetables and fruits, if stored a t temperatures above 0" F., lose their color, flavor, and vitamin C content. Meats require 0" F. or lower. The higher the temperature, the sooner the fat becomes rancid and objectionable flavors in themeat develop. Pork is the most sensitive. It becomes rancid in 2 months a t 15' F. and in four months a t 10" F.; but a t 0" F. there is no sign of rancidity a t the end of a year. Reef, lamb, and veal are more stable, but show signs of rancidity in the fat a t the end of 3 months a t 15" F. and of 5 months a t 10" F. At 0" F. they are free from rancidity a t the end of Courtesy, Refrigerating Engineering 12 months. . A Meat Cutting Room in a.Frozen Food Locker Plant F r o z e n food l o c k e r plants are a great asset i n t h e f e e d i n e : of civilians. Scattered in rural communities in every state, Farm freezers easily accessible, and, in general, efficiently refrigerated, they I n addition to locker freezers for public use, cabinets with constitute a food bank which is capable of far wider usefulself-contained freezing units have been manufactured and ness as the pinch of a civilian food supply develops and the termed "farm freezers". They range in capacity from 10 to necessity for the conservation of every pound of food pro30 cubic feet, are provided with a small refrigerating machine duced becomes apparent. Already some locker plants are capable of reducing the temperature of part of the space to acting as exchanges where the surplus from one farm and - 10" F. and of holding the remainder a t 0" F. or a little above, shortages on another can be equalized. Occasionally a locker and are generally operated on motors of 1/3 to 1 horsepower. plant does a merchandising business in frozen foods and These farm freezers were just becoming popular when their there are potential possibilities in this direction should our production was discontinued for the duration. However, 40,000 retailers be insufficient. enough of them have been distributed to show that they are practical and economical and, in the present emergency, highly desirable for farm homes. Refrigeration of ships stores Aside from the conservation of tons of perishable foods, the The war emergency found us with land-based refrigerating locker plants and farm freezers have led to a much wider facilities and processes sufficiently flexible to permit their knowledge, especially on the part of housewives, of fruits, utilization as necessity indicates and, with good planning, vegetables, and the cuts and kinds of meats. The quick fairly adequate for the work to be done. But the job to be frozen industry pioneered in the study of the kinds of produce done on the seas is new, and for the exigencies of the present to grow for freezing. Seedsmen have become familiar with situation we have a t least one outstanding lack-namely, the varieties of fruits and vegetables that will freeze satisrefrigeration for the preservation of ships stores. Our factorily, and can advise customers wisely. Home demonmerchantmen carrying supplies to troops and to our allies stration agents and county agents are ready and able to exmust frequently provision for a round trip of six months. pound and explain conservation by freeaing. Locker plants During that time the only food t o be depended upon is that have printed and distributed, free of charge, booklets giving supplied the ship before it left the United States port. instructions for preparing goods for freezing. State experiThe old days have gone by when salt pork, canned potatoes, ment stations have published excellent bulletins based on the and dried apples were the menu for the ship's crew. Now research work of their own staffs. Altogether, the many the men must have a balanced American diet with fresh educational agencies have transferred a large section of the meats and poultry, vegetables and fruits, eggs for breakfast, public mind from an ignorant prejudice against frozen foods fresh milk as long as possible, ice cream and newly baked to an enthusiastic acceptance of them. cakes, and an abundance of fruit juices to ensure against In the early days very few lockers kept temperatures scurvy. Recent studies of dietaries state that a sailor in our steadily below +lo" F. and almost none maintained 0" F. Navy consumes 1985 pounds of food per year, a soldier, 1844 Consequently the products spoiled. As a result, condempounds; while a sailor in the Merchant Marine requires nation of the whole project was widespread. State food 2555 pounds or about 7 pounds per day. Given a wartime authorities then took a .hand in the proceedings and issued crew which is ordinarily increased from 30 to 60 per cent, the instructions and orders. State experiment stations instituted problem of space in which to stow sufficient food becomes research based on the preservation of perishables under I
extreme, quite aside from preserving it in palatable condition. No one who has ever gone down to the sea in ships can begrudge the crews good food, as Americans know good foods, and the ship operators are going to every length to provide an excellent and attractive dietary. But while fruit shippers and meat packers, knowing the refrigeration ~ e ~ u ~ e m e of n t stheir comodities, have cooperated with shipbuilders in the refrigeration of cargo space, apparently no one has applied the universally accepted ternperatures for food p r e s e ~ v ~ t i oto n the space for carrying ships stores, Rohn and Clarke (49 state that in the new cargo ships the service compartment for meat carries a temperature of 2 to 26" F. 'Fish is kept a t 26" F.and dairy products at 45" to 60" B'. I n pmsenger and cargo ships the temperatures in e from % 5 O to 20" F., and ice cream a t 26 to temperatures (3) for c t ~ dbelow, fish 0" to --IO", ' to -2O", and egm in the shell the facts, we may expect eggs
m possible and dehydrated foods are increasing, but in theere days fresh. foods must form a portion of the ration. Quick frozen foods for ships storm, wo far as space and weight saving are concerned, are ideal, but thcy m x a t be held at Las F. or lower. n and CEarlae have been The temperatures given by bequeathed to our merchant by the .European whipbuilders. They are the temperatures in use in Great Britain neither of which uses low tenriperahree esican sense of the art. According to Raymond (2% E the newest ~ e ~ r ~ g c r r ~ t~ed~ ~bi~ilt, /PI r ritain. during the war ha ttan ~ e ~ tiown& ~ better than %%be%Peo
&e,the ship'a operator might in various ways cornpen of preservation tern~ e ~ a ~Now ~ hia ~ e s ~ ated Mpiice mmst act as a cold storage ~ a ~ ~ ~ o u s e o n t h , a ~ O n M i d e ~ ~ ~ ~ y longer t h e than the average period in land warehouses. It would seem imperative thsat attenti0 given at once to the ~ ~ ~ e r of~ food ~ ~for~ crew o nand . sengers aboard ship under present conditions.
poultry to develop rancidity lasts for more than B few weeks. ler (6) reports u ~ ~ rancidity e ~ in pork ~ rin 2~ ~ terature ~ ~ cited months at 16" F., "while beef, lamb, seal, and chickens be(1) Plank, R.,z. allyem. Physiol., 17, 221-38 (191%). (2) R ~ r y m o ~ iTheodom, d, Ref& Enq.t come ~ ~ ~ ~ e rancid a s ~is, nthree ~ ~ months y when held at R4friperating Dsta I%Oi9b, Voi. 2 ( I ~ the products ~ held t a t IO" ~ to 1 o6 O K?. ~ Yd) ~ " I?.". In ~ (1) Realm, A. c.,and, @iarko, "1-E L * 12CJ
d l progress even more rapi ly. Canned goods are used 8 8 far
~
c
and Dup%ois,B. W. Bull. 690 (1940).
(51 Trerssler, D,
A E$ P Bakeries, The Great A B P Tea Company, New York, N. 'Y.
Jf-IE ~ o r t ~ f i ~ Of ~ t food ~ o n P P O d b l C h ha8 beegB EL&& PO$-
sibk 86 a result of the investigation, iso%atioe,and syatheses of vitaxains. Many of these itid id Pttnmirss (and ak0 mineKrtk$ Can HlOW be d d e d aCOnoDliC&lig to OU?' coPIUYIon foo&. The fortification of products with certain of these nutrients has been practiced for several years, 6-Iowever, most of the fortified products haye not been a part of any national program whereby the welfare of the Nation as a whole would be benefited. Most of the products fortified have been those that are not generally used by people in the low income brackets, either because of p r ~ ~ ore because ~ ~ n ~ ~
~ ~
