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MODE AND RATE OF HEAT TRANSFER IN CANNED MEATS
MODE AND RATE OF HEAT TRANSFER IN CANNED MEATS
Pages 38-139
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From page 38... ...
That has to do with the mode of heat transfer in canned meats, and our first speaker on that this afternoon will discuss "The Effect of Processing Temperature upon the Rate and Pattern of Heat Distribution within a Can of Beef." He is Dr. Tischer, formerly of Iowa State College, now director, Food Laboratories, Quartermaster Food & Container Institute for the Armed Forces.
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From page 39... ...
i , t t « 1.5* -^1 i time zero followed by ellipsoidal distributions as time progresses and ending in a small sphere or a true geometric point at some later time in the process.
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From page 43... ...
As time progresses at each temperature it should be noted that the isothermal lines tend to close at the center forming a roughly circular area located to the right of the can center and either on the horizontal central axis of the can or somewhat above or below it. These effects appear to be approximately the same at each of the representative processing temperatures used, suggesting that the effect of processing temperatures on this occurrence may be negligible.
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From page 44... ...
Effect of Ingredient Arrangement on the Rate of Heat Transfer in Canned Meat Products C OLIN BALL In conventional practice, a product requires severe heating during the sterilizing process because heat is transmitted through the product by conduction and therefore travels very slowly.
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From page 45... ...
STRATIFICATION or COMPONENT PARTS OF CREAM STYLE CORN IN THE CAN. Courtesy of Food Industries (now Food Engineering)
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From page 46... ...
Four different formulated meat products were studied at Rutgers University in a project sponsored by the Quartermaster Food and Container Institute for the Armed Forces. These were ham and beans in molasses sauce, frankfurters and beans in tomato sauce, beef and vegetables in gravy, and meat balls and spaghetti.
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From page 47... ...
RELATIVE RATES OF HEAT PENETRATION INTO STRATIFIED AND PREMIXED CREAM STYLE CORN IN CANS OF 4 SIZES. Courtesy of Food Industries (now Food Engineering)
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From page 49... ...
These results are presented in Table 1. TABLE 1 HEAT PENETRATION AND PROCESS DATA -- HAM AND BEANS IN MOLASSES SAUCE Arrangement > III IV V f» 34 24 27 80 f, 51.5 X'*
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From page 50... ...
The above results, together with heat penetration data, are given in Table 2. TABLE 2 HEAT PENETRATION AND PROCESS DATA -- FRANKFURTERS AND BEANS IN TOMATO SAUCE Arrangement > I II III fbl 8.2 5.6 7.7 34 22.5 *
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From page 51... ...
TABLE 4 LOCATIONS OF CRITICAL POINTS -- FRANKFURTERS AND BEANS IN TOMATO SAUCE Amount Tomato Pulp Arrangement I Arrangement II 100% Specification 50% Specification Sauce Layer Sauce Layer Near Bottom Sauce Layer Sauce Layer Near Bottom For the product having 50% of the specified amount of tomato pulp, the required process when filling arrangement either I or II is used is approximately one-half as long as that required when the product is formulated and packed according to Military specifications (arrangement III)
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From page 52... ...
This indicated that the sauce layer was not of uniform thickness and that a thick part was away from the axis. Heat penetration data and calculated processes are shown in Table 5.
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From page 53... ...
Spaghetti and meat balls. The last of the formulated meat products to be studied, spaghetti and meat balls, gave variable results.
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From page 54... ...
When this packing and processing procedure was introduced a few years ago, justifiable skepticism was expressed as to whether or not the stratified layers would remain stratified during the heat sterilizing process. Experience not only with corn but also with the meat products discussed herein has shown that this skepticism was not justified ; on the other hand, the only problem involved here points in the opposite direction -- the difficulty of reconstituting the product.
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From page 55... ...
Summary Heat penetration tests were made of 4 formulated meat products, used as ration items by the Armed Forces, in which the component parts were stratified in the can during processing so that the portion in the center of the can would be heated by convection and the portion in one or both ends of the can would be heated by conduction. Processes calculated from the heat penetration results showed that sterilization can be accomplished in the stratified products in much less time than in the same products formulated and packed in accordance with Military specifications.
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From page 56... ...
Preliminary Observations on the Effect of Can Movement During Thermal Processing JAMES M BLAIR It has been obvious for many years that the conventional methods of stabilizing canned meats by heating with steam have been very deleterious to the quality of the product.
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From page 57... ...
Very likely, this lack of investigation has been due to the common and perhaps justified belief that the more or less solid or viscous canned meat products transmit heat slowly and, because of FIGURE 2.
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From page 58... ...
The purpose of this investigation has been to consider the principles of agitation of canned meats and to determine the extent to which they can be utilized to improve canned meats. The data obtained to date are preliminary in nature, but with the accumulation of additional experience, it is anticipated that it will be possible to determine the extent to which agitating processing will improve the general quality of canned meats.
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From page 59... ...
. Powdered laboratory-grade bentonite was added, with TABLE 1 SUMMARY OF TEST PROCEDURES USED TO DETERMINE THE EFFECT OF END-OVER-END AGITATION OF THE RATE OF HEAT PENETRATION IN VARIOUS MATERIALS Purpose of Experiment Test Material Test Conditions To determine optimum r.p.m.
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From page 60... ...
The 2 food products tested, frankfurters and pork luncheon meat, were prepared according to Military specifications covering the manufacture of these items. Again, net weight, gross head space, vacuum, and thermocouple position were carefully noted.
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From page 61... ...
agitated cans, and the 3 thermocouples recorded essentially the same temperatures during the heating period. On the basis of this and other similar determinations, the agitation speed considered to be optimum in resulting in the greatest rate of heat penetration in products similar in density to a 5% bentonite dispersion is in the range of 36 r.p.m.
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From page 62... ...
Induced convection heating. Induced convection heating is a term applied to the heating characteristics of a substance with such a viscosity as to cause the product to exhibit conduction-type heating characteristics when still cooked and yet be of thin enough consistency to permit flowing when agitated and thus demCon Sue 401 « 411 Retort Temp « 240 "F Still-Cooked Cons, vefticol Position Agitoted Conv End-Over-Cnd 36rpm 40 50 60 TO 10 TIME-MINUTES FIGURE 7 RATE OF HEAT PENETRATION IN LUNCHEON MEAT DURING "AGITATED" AND "STILL" COOKS 62
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From page 63... ...
Thus, the physical nature of a 10% bentonite dispersion is representative of products for which agitation will offer little advantage in increasing the rate of heat penetration. Luncheon meat, as indicated by can No.
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From page 64... ...
Discussion These preliminary observations on the effect of can movement, or agitation, during heat processing have been primarily intended to indicate the procedures to be used in the experimental agitated processing of canned meat products. Bentonite dispersions of various concentrations have proved to be useful in establishing some of the fundamental characteristics of agitating-retort procedures.
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From page 65... ...
Canned meat products essentially solid and uniform throughout deserve specific consideration because of the particularly excessive amounts of heat required for their sterilization during conventional retorting. As indicated by the unaffected rates of heat penetration obtained in 10% bentonite suspensions during agitated retorting, it appears likely that agitation will be of no value in decreasing required heating time in canned meats possessing similar consistency.
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From page 66... ...
Materials similar in consistency to a 10 % bentonite dispersion are therefore classified as strict conduction-heating types. The heating characteristics of most canned meat items involve a combination of methods of heat transfer described above and are classified as combination conduction-convection heating types.
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From page 67... ...
However, the meat that we studied wasn't as fresh as even 2 or 3 hours, and so the counts reported do not reflect the living animal condition at all. The counts of putrefactive anaerobes were made low in order to eliminate anaerobic organisms -- the only way we thought it possible was to heat the material to 80°C.
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From page 68... ...
But usually the count ranged between 10,000 and a million on the surface. Below the surface there aren't many organisms, or we haven't found many organisms; with the fresh meat, we found very, very few organisms, even slightly below the surface.
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From page 69... ...
Probably many of you remember that several years ago the American Meat Institute reported they could find viable spores in the tissue of living animals. That may well be the case.
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From page 70... ...
Halvorson has any thoughts on the subject. HALVORSON The experiments we did on spores in rancid fats -- reported by Jackson and Foster -- show that the fatty acid inhibits the germination of spores.
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From page 71... ...
Brissey's question -- we ran into the same thing in the luncheon meat, entirely separate packs, where on long storage we got no spoilage, and there wasn't any survival. Apparently, the organisms were non-viable.
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From page 72... ...
because there is no moisture for them to grow on. They have just died of old age, I suppose.
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From page 73... ...
SUGIYAMA Mr. Chairman, along that line, it has been proved many times that spores subjected to rather severe heat treatments are much more fastidious in their nutritional requirements for growth to take place.
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From page 74... ...
I can say this, that if one determines the moisture content and the equilibrium vapor pressure of spores at different moisture levels and of vegetative cells at different moisture levels, we come to the conclusion that the vegetative cell likes water better than the spore does. The vegetative cell is more lyophilic than the spore.
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From page 75... ...
MEYER (QMFCI) Aside from the bacteriological problems discussed here today, I wonder if any thought has been given to just what can be done with canned meats from a technological point of view.
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From page 76... ...
CHAIRMAN ROBINSON I have thought for quite some time about this problem of more acceptable canned meats. From the industry's viewpoint, you are aware it is not a very satisfactory business.
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From page 77... ...
The consumer is therefore less content with a canned product. That's our reason for having a fresh-tasting piece of properly cooked meat as our canned meats goal.
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From page 78... ...
When we buy canned meats we buy large quantities as assurance that we can feed the soldier in the field under extreme combat conditions where you cannot get refrigerated products. We try to get fresh food there whenever possible, but to do that, we do have to carry large reserves of canned meats, and we do have to eat them.
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From page 79... ...
Canned meat is an extremely important problem to the Armed Services. If you ever develop canned meats that are really highly acceptable to the soldier, he will change the tastes of the civilian market because he has done it in other wars when he came back.
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From page 80... ...
CHAIRMAN ROBINSON Colonel Jackson, we are in perfect accord with what you have said. I actually went on a fishing trip 2 years ago and bought all kinds of canned meats I could get.
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From page 81... ...
Colonel Jackson's remarks on canned meat acceptance made me wonder whether or not there would be a question of nutritional quality involved. His remarks seemed to me to indicate that the soldiers will eat until they reach the point of disinterest or not caring.
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From page 82... ...
Levin, assistant chief, Military Operations Office, Quartermaster Food and Container Institute, formerly was an infantry officer and served in the European, Pacific, and Korean theaters. He is well qualified, obviously, to explain "Why We Need Better Canned Meat Products." Major Levin.
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From page 83... ...
This ration centers around canned meats and it might be said that: regardless of the soldier's location, whether on the Operational Line of Resistance or the Main Line of Resistance, whether his food is served hot or cold, the food he eats is processed food, usually in the form of canned foods. It is therefore essential that it be appetizing, continuously acceptable if possible, and nutritious.
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From page 84... ...
Canned meat products are of prime importance in combat rations. These products are central to the ration, and upon them the effectiveness of the ration as a whole depends.
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From page 85... ...
SMITH, JR. In this discussion on sterilization of canned meat products the destruction of pathogenic and spoilage organisms by heat alone will be considered.
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From page 86... ...
In considering available means to secure rapid heating of the product, 3 basic methods offer possibilities. If the largest discrete particle is of small dimensions, it is possible to secure satisfactory heat transfer by simple conduction from a heated surface.
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From page 87... ...
It can be definitely stated that with exercise of reasonable care there is no industrial hazard involved in working at pressures of the order of 20 pounds gauge. The application of the Smith-Ball process to meat products such as hash, Vienna sausage, frankfurters, luncheon meats, hamburgers, and any other type of meat products that are of relatively small dimensions in at least one direction, can be quickly heated to acceptable temperature values by means of heat exchangers designed to the physical requirements of the products, by surrounding the product with steam, by cooking in water or high-boiling liquids such as cooking oils, etc.
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From page 88... ...
physical dimension of the article being heated. If we assume that 10 cm.
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From page 89... ...
can, condensation of the water vapor within the head space immediately occurs, thereby reducing the pressure within the container. This, in turn, causes boiling or evaporation of additional moisture.
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From page 90... ...
Personnel entering the airlock or entrance vestibule can be brought up to operating pressure in a very short time, the only limitation being a slight discomfort if the Eustachian tubes are abnormally small or inflamed or irritated by a head cold. If the pressure changes too rapidly for equilibrium to be established in the inner ear through the Eustachian tubes it is simply a matter of personal comfort to decrease the rate of pressure change.
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From page 91... ...
Potentialities of Utilizing a Continuous Type of Process in Conjunction with Aseptic Canning for Production of Canned Meat Products JOHN P BOLANOWSKI Although the approaches to a discussion such as this are numerous, it is felt that the potentialities of this method of canning some types of meat products can best be illustrated by attempting to bring to light the prerequisites of the process and the problems involved in fulfilling these prerequisites.
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From page 92... ...
In addition, this pumping system must not damage the product or cause the discrete particles to lose their identity as, for example, creamed beef or cream-style corn.
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From page 93... ...
f. By proper design of the shaft and control of the annular space, products containing discrete particles have been successfully processed, as for example, cream-style corn, dog food, creamed chipped beef, cream of mushroom soup, etc.
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From page 94... ...
At this time we come to the point where it is appropriate to ask: What are the potentialities of utilizing a continuous type of process in conjunction with aseptic canning for the production of canned meat products? Over the past 3 years a number of meat products have been flash sterilized and aseptically canned at Louisville, Kentucky.
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From page 95... ...
This results in the typical overcooked flavor and poor texture of many canned meat products, particularly those processed in large size containers. To overcome these disadvantages, several new techniques have been proposed and are being investigated in several laboratories.
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From page 96... ...
If high-frequency heating is to be used for processing meat products for canning, the temperatures attained in a definite time must be uniform throughout the body of the meat. We have been able to attain reasonably uniform temperatures in pork luncheon meat along the entire axis of the meat cylinder (Table 1)
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From page 97... ...
Sterility of products processed. To determine whether or not meat products could be effectively processed from a sterility standpoint, pork luncheon meat, ground fresh pork, and ground beef were inoculated with spores of the culture of putrefactive anaerobe designated as P.A.
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From page 98... ...
Practical evaluation and application of high frequency heating for canned meat products The results reported indicate that high-frequency heating can be applied for the processing of canned meat products if only the quality of the processed meat and sterilization effectiveness are considered. From a practical and technological standpoint, however, there are some very important problems to be solved.
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From page 99... ...
Although we are attempting to develop materials and techniques that may overcome this 2nd disadvantage, the solution of the problem is not yet in sight. Summary Pork luncheon meat and boned hams may be heat processed by means of high-frequency, dielectric-type heating.
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From page 100... ...
This discussion will be concerned with the second method, intermittent heat treatment. A canned meat product, intended for Armed Forces use, must possess a minimum stability equal to 6 months at 100°F.
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From page 101... ...
Details of the patent as applied to raw cured ham are quite similar to those described in this paper. Experimental Procedures In December of 1951, production of 182 hams by the method described in the patent, "Production of Canned Meats for Storage," was completed.
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From page 102... ...
and kept there overnight. On the second day of processing, the canned hams were again placed in the cooking tank and given the following process: 2% hours at 127° F
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From page 103... ...
* 1 2 3 4 5 8 7 1« 20 21 22 23 24 25 88 27 28 29 SO 31 32 HOURS FIGURE 1 PROCESSING SCHEDULE FOR CANNED WHOLE HAMS -- INTERMITTENT HEAT TREATMENT 4% hours at 170° F
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From page 104... ...
It was decided that in addition to initial examinations, the canned hams would be subjected to storage for periods up to one year at temperatures of 40° F (the control)
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From page 105... ...
Chemical analyses included determinations for moisture, ash, fat, protein, chlorides as NaCl, sodium nitrite, and sodium nitrate, reducing sugars and total sugars as dextrose. The peroxide value and free fatty acid development were measured.
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From page 106... ...
Vacuum data are inconclusive, except it might be noted that this process produced a maximum vacuum of 5 inches in this test. Bacteriological examination showed both aerobic vegetative types and anaerobic spore-forming organisms in the canned hams at the beginning of storage.
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From page 107... ...
'' Detailed results of all aspects of the technological, bacteriological, and chemical tests reported herein are available upon request to the Quartermaster Food and Container Institute for the Armed Forces, 1819 W Pershing Road, Chicago 9, Illinois.
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From page 108... ...
This has led to consideration of using ionizing radiation to sterilize food and thereby prevent food spoilage resulting from the action of microorganisms. One such application would be the substitution of radiation sterilization for thermal sterilization in the processing of canned meats and other foods.
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From page 109... ...
This research was begun in the summer of 1951 when the Fission Products Laboratory of the Engineering Research Institute received a one-kilocurie cobalt-60 source of the type described by Manowitz U)
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From page 110... ...
Animal feeding experiments. A few months after receiving the one-kilocurie gamma source some preliminary animal feeding experiments (2)
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From page 111... ...
The feeding experiment to establish the wholesomeness of irradiated food should be independent and not combined with an experiment which might involve the dosage of radiation required for sterility. If the animals are given food in which the wholesomeness of the food is independent of the requirements of sterilization by radiation, using food such as canned milk or canned meat which is sterilized thermally, the variable of radiation dosage required to sterilize the foods will not influence the experiment.
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From page 112... ...
The original one-kilocurie source received by the Fission Products Laboratory has been useful in exploratory studies but has limited use because of the small size of the opening. No commercial size tin can would fit into this source and all experiments with irradiated food were conducted with glass test tubes or plastic bags as containers.
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From page 113... ...
10 size tin container, whole hams and sufficient volumes of food to conduct appropriate animal feeding experiments. It has been estimated that the new 10-kilocurie cobalt-60 source in the Fission Products Laboratory has increased the irradiation facilities at this laboratory perhaps more than 30-fold.
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From page 114... ...
GOLDBLITH Over the past few years, it has been demonstrated that destruction of microorganisms in any organic or inorganic medium can be achieved by bombardment with ionizing radiations, irrespective of whether the container holding the medium is of metal, glass, or fiber. For most of the research in this field, cathode rays or beta particles produced in particle accelerators of various types have been used, and canned meat products are among those foods that have received considerable attention to date.
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From page 115... ...
The purpose of this paper is to outline the present-day status of the sterilization of canned meat products by high-energy cathode rays and the requirements and methods to meet the objectives in such sterilization. Equipment.
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From page 117... ...
The efficiency of penetration of the electron beam energy when conventional sardine cans are crossfired is illustrated in Figure 2. It is to be noted that the can cover absorbs a great deal of the energy available as pointed out by (4)
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From page 118... ...
The design and development of particle accelerators of such energy levels, with a sufficient flux of electrons, are necessary for containers of greater thickness. The linear electron accelerator may offer a means of achieving such voltages in the near future, if further deN 100, 80 A H 0 V 2CE R 2.0 ~0 2 .4 .6 .8 1.0 12 1.4 16 PENETRATION (cm)
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From page 119... ...
One may summarize the equipment factors to be taken into consideration in the radiation sterilization of meat as follows: Particle accelerators for electron acceleration having a range in voltage of from 1 to 3 m.e.v. have been designed and fabricated.
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From page 120... ...
The product. Sterilization of canned meat products by cathode rays, insofar as the product is concerned, involved most of the factors that are present in sterilization with isotopic sources of beta- or discussed in detail previously (4, 5)
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From page 121... ...
An effort has been made to present factually the pros and cons of cathode ray sterilization in regard to meat at this time. In summary, it may be said that the sterilization of meat products by ionizing radiations offers a number of problems common to both accelerator and isotopic sources of radiation.
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From page 122... ...
The present status of radiation sterilization of meat and meat products, insofar as the product is concerned, has been discussed in detail. Although the data presented show that a great deal of research is yet to be done to make this process commercially feasible, a brief glance into the recent past shows that much has been accomplished in the few years that this method has been studied by the relatively small number of investigators in the field.
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From page 123... ...
Doty, in connection with organoleptic qualities of food heated dielectrically and that heated by steam methods, what kinds of steam methods you were referring to -- whether they were fast heating or not? DOTY In the case of the pork luncheon meat, comparison was made between dielectrically processed meat which we prepared and the pork luncheon meat as processed at the Food and Container Institute using 123
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From page 124... ...
We would assume, and we have found, that conventional methods with pork luncheon meat or chopped ham give better results on color, flavor, texture, and sliceability than we obtained on this particular study with this ham.
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From page 125... ...
HARRY SPECTOR (QMFCI) As a contribution to the over-all nutritional adequacy of the operational ration, canned meats have an important function.
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From page 126... ...
In other words, when a product like spaghetti and meat is considered the spaghetti gets rather soft after a period of one year or possibly sooner at elevated temperatures; thus, there is some change even though we have an advantage at the start. We do get some change after prolonged storage, and particularly at 100°F., which is a very severe temperature for storage of meat products.
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From page 127... ...
CHARLES NIVEN (American Meat Institute Foundation) What proportion of the canned hams used in the Institute experiment that were sto*
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From page 128... ...
coli. SPECTOR With reference to the canned meat items in the C Ration, the chart shows some 10 canned meat items, but the menu is so arranged that the C Ration consists of 6 different menus and 3 different meat items in each menu.
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From page 129... ...
He still would like the frozen and fresh meat, but we must remember there are many times when he cannot get it, and what we would like to get from you people is better canned meats. That is the principal reason for asking for that advancement of canned meats.
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From page 130... ...
LARSEN (QMFCI) It is my understanding that meat and other products deteriorate in storage for 2 reasons -- the growth of microorganisms in the meat products and also because of the action of the enzymes which are inherent in the meat.
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From page 131... ...
If you produced meat under strictly aseptic conditions, would you have to worry about storage properties? CHAIRMAN WIESMAN Would anyone else like to comment on that?
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From page 132... ...
Whether that validates the use of antibiotics or not, I don't know. CHAIRMAN WIESMAN It is a legal problem, I guess.
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From page 133... ...
DOTY Actually, the proportions of moisture in fat and in protein influence the proportion of energy which heats by means of the capacitance of the material and resistance in the material, so if one were to increase the moisture content, one should increase the capacitance and decrease the resistance. With an increased moisture content you expect to get a higher proportion of capacitance through dielectric heating, if you please, and less and less resistance heating.
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From page 134... ...
CHAIRMAN WIESMAN Dr. Nickerson stated, from the standpoint of ionizing radiation, that they were not destroyed, but they have no storage studies.
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From page 135... ...
CHAIRMAN WIESMAN Thank you very much, and thank you all for your kind attention. (The meeting adjourned at 4:15 o'clock.)
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From page 138... ...
Armed Forces Food and Container Institute (U.S.) The quality and stability of canned meats
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From page 139... ...
Garnatz Emil M Mrak Director, The Kroger Food Foundation Professor of Food Technology University of California W
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