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Укажите предложения, соответствующие содержанию
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Текста В.
1. Three general levels of heat processing are employed in meat preservation.
2. A moderate heating process kills all microorganisms present in meat?
3. Pasteurized meat products must be stored under refrigeration after being processed.
4. Heating by radiation is the transfer of heat energy through space.
5. It is important to consider fundamental heating principles when thermal processing schedules are developed for a meat product.
6. Thermal processing to achieve sterility is usually done in open vats.
7. Temperatures of 120*C or higher are commonly achieved in the retort.
Прочитайте три отрывка. Озаглавьте каждый отрывок и скажите, какие из них дополняют информацию текстов А и В.
1. Once, the manufacture of meat products was strictly an art handed down from generation to generation. Today, the development of new products and the improvement of old ones is a science. Major research programs in Meat Science are being carried on at universities, research institutes, and government research facilities in this country and abroad. Because of this research effort, the past decade has seen a tremendous expansion of the basic science of meat as a food. Since many basic questions remain unanswered, and new technical problems frequently arise, there is still much fertile ground to be plowed by the imaginative scientist. Meat Science is a broad field of study, an important part of which is the basic study of the unique characteristics of muscle and the other animal tissues that are used as meat. A complete understanding of the basic properties of the tissues used in meat can lead to improved utilization and better meat products. Meat Science is not limited to the study of tissues. It includes all facets of the meat industry, beginning with animal production and ending with final preparation for consumption. Breeding, feeding, and management are extremely important parts of the food chain because quality control actually starts on the farm, ranch, or feedlot.
2. The thawing process probably does greater damage to meat than freezing. Several factors are largely responsible for the damaging effects that occur during thawing. First of all, thawing occurs more slowly than freezing, even when the temperature differential is the same. However, the temperature differential in thawing is generally much less in practice than that encountered in freezing. Secondly, during thawing the temperature rises rapidly to the freezing point, but then remains there throughout the entire course of thawing. This situation further increases the length of the thawing process, compared to freezing. The thawing process thus provides a greater opportunity for the formation of new, large ice crystals (recrystallization), for increased microbial growth, and for chemical changes. An additional potentially serious problem is that most thawing is done at the point of consumption by individuals who generally have little knowledge of the problems associated with thawing meat products. Meat products may be thawed in any of several ways: (1) in cold air, such as in the meat cooler or home refrigerator, (2) in warm air, (3) in water, or (4) during cooking, without prior thawing. The time required for thawing frozen meat products depends upon a number of factors. Among the more important of these factors are: (1) the temperature of the meat product, (2) the thermal capacity of the meat product (lean meat products have higher thermal capacities and therefore thaw more slowly than do fat meat products), (3) the size of the meat product, (4) the nature of the thawing medium (water provides faster heat transfer than air), (5) the temperature of the thawing medium, and (6) whether or not the thawing medium is circulated.
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3. Hot air drying. Acceptable quality comminuted, cooked meat products can be produced by hot air drying. However, such factors as temperature, particle size, and the rate of air movement must be carefully controlled. Meat products dehydrated in this manner have a residual moisture content of about 5 percent. As a consequence, certain deteriorative changes can develop during prolonged storage. The fat, especially that of pork, tends to become rancid following hot air drying. This can be retarded either by the addition of antioxidants, or packaging the product in a manner that eliminates oxygen. Hot air drying is a slow process that is not applicable to uncooked meat or to large pieces of cooked meat (such as roasts, steaks, or chops) because the resultant surface hardening yields a product with poor consumer acceptability. Meat products dried by hot air also shrivel considerably, and have poor rehydration properties due to the protein denaturation that occurs during the drying operation.
22. Обсудите информацию отрывка 1 в парной беседе. Для этого составьте 5-6 вопросов к отрывку и задайте их своему товарищу. Ответьте на его вопросы.
23. Ответьте на вопросы к отрывку 2.
1. Why does the thawing process do greater damage to meat than freezing?
2. What is an additional serious problem associated with thawing meat products?
3. How many ways of thawing are there in use?
4. Does the time for thawing frozen meat products depend on their size?
5. Which meat products thaw more slowly, lean meat products or fat meat products, why?
Переведите отрывок 3 письменно с помощью словаря.
Прочитайте текст С и скажите: а) каково назначение упаковки для пищевых продуктов? б) есть ли отличие в упаковке для свежего мяса и продуктов, подверженных посолу?
Слова для понимания текста С:
requirement – требование
damage – вред, повреждение
merchandise – торговать
discolouration – потеря цвета
impermeable – непроницаемый
moisture proof – влагостойкий
film – плёнка (упаковочная)
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overwrap – обёртка, верхняя оболочка упаковки
«boil in the bag» - варка продукта в упаковке
seal – закупоривать, запечатывать
pliability – гибкость, пластичность
Text C
Packaging Requirements and Materials
The principal functions of meat product packages are to provide protection against damage, physical and chemical changes, further microbial contamination, and to attractively display the product to the consumer. Thus, packages are designed to maintain the quality of the product that is placed in it, but they can not improve that quality in any way.
The packaging requirements for fresh and cured meat differ primarily due to the chemical nature of the pigments that are present. One of the most important considerations in meat merchandising is that of maintaining an optimum color. In fresh meat, the optimum color occurs when the packaging materials used allow a sufficient amount of oxygen to pass through them. On the other hand, the packaging materials must be moisture proof in order to prevent product dehydration and surface discoloration. In contrast to fresh meat color, the retention of a stable color in cured meat depends upon the absence of oxygen. Therefore, the packaging requirements for cured meat products necessitate the use of materials that are oxygen impermeable. As in fresh meat, the packaging materials for cured meat products must be moisture proof.
The packaging materials for both fresh and cured meat must protect the product from further microbial contamination during all subsequent storage, handling, and merchandising. Packaging materials must not impart any odor or flavor to the product, and they should retain the natural flavors and odors that are inherent to the product. The packaging requirements for frozen meat include low moisture vapor transmission, pliability, strength, and grease resistance. The overwrap films used in packaging meat for retail display should be strong, have good stretch and heat sealing properties, and retain the seal under normal storage and handling conditions. The packaging materials used for "boil in the bag" meat products must withstand the freezing conditions, freezer storage temperatures, and the rigorous temperature changes encountered during cooking.
A large number of materials are available for the packaging of meat products. These include glass and metal containers, aluminum foil, paper and paper board, cellophane, a large number of films manufactured from polyethylene, polypropylene, polyesters, nylon, polystyrene, polyvinyl chloride (PVC), saran, and chemically treated rubber (Pliofilm). Combinations of these materials, called laminates, are prepared by bonding together two or more papers, films, or foils to produce a packaging material with a wide variety of functional properties that depend upon the materials used in the laminate.
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