It is often stated by those in the meat and refrigeration industries that 'anyone can measure a temperature. Many millions of measurements are made of both meat and environmental temperatures in the meat industry. However, in many cases the measurements made are an unreliable guide to the effectiveness of the refrigeration process. Even when the correct tem- peratures have been obtained the data are often poorly analysed and rarely acted upon

Since the mid-1980s there has been a considerable increase in legislation defining maximum temperatures during the production, distribution and retailing of chilled food. However, as soon as the food is purchased by the consumer, it is outside of any of these legislative requirements. Increasingly food poisoning incidents have been found to be due to mishandling of food in the home with insufficient refrigeration or cooling being the most fre

Theoretically, there are clear differences between the environmental con- ditions required for cooling, which is a heat removal/'temperature reduction process, and those required for storage where the aim is to maintain a set product temperature. However, in many air-based systems, cooling and storage take place in the same chamber and even where two separate facil- ities are used, in many cases not all the required heat is removed in the

Thawing has received much less attention in the literature than either chill- ing or freezing. In commercial practice there are relatively few controlled thawing systems. Frozen meat, as supplied to the industry, ranges in size and shape from complete hindquarters of beef to small breasts of lamb, although the major- ity of the material is 'boned-out' and packed in boxes ca. 15 cm thick weigh- ing between 20 and 40kg. Thawing is usually regarded as complete when the centre of the block or joint has

From the moment an animal is slaughtered the meat produced begins to lose weight by evaporation. Under typical commercial distribution condi tions, it has been estimated that lamb and beef lose from 5.5 to 7% by evap- oration between slaughter and retail sale(Malton, 1984). Weight losses from pork are probably of the same magnitude. In addition to the direct loss in saleable meat there are also secondary

The appearance of meat at its point of sale is the most important quality attribute governing its purchase. The ratio of fat to lean and the amount of marbled fat are important appearance factors and another is the colour of the meat. The changes in colour of the muscle and blood pigments (myoglobin and haemoglobin, respectively) determine the attractiveness

Microbiology of refrigerated meat There are many pertinent texts on the microbiology of meats. The purpose of this chapter is to examine briefly the types of micro-organisms and con- ditions that are of interest in relation to the refrigeration of meat and meat products. In a perfect world, meat would be completely free of pathogenic(food poisoning

制冷技术( Refrigerat ion Techno log 是一门研究人工制冷的原理、方法以及如何运用制冷装置获 得低温的科学。 低温是相对于环境温度而言的,从低于环境温度的空间 或物体中吸取热量,并将其转移给环境介质的过程就是制冷 。它是为适应人们对低温的需要而产生和发展起来的

压缩机作为主机 一类是主要设备:冷凝器、蒸发器、节流机 构等,这些是完成制冷循环必不可少的设备 另一类是辅助设备:各种贮存、分离和安全 保护等设备,这些设备的作用是改善制冷系 统的工作条件,提高系统运行的经济性和安 全可靠性

在蒸气压缩式制冷装置中,选用 了各种类型的制冷压缩机。它们是装置 中的关键核心设备,对系统的运行性能 、噪声、振动、使用寿命和节能有着决 定性的作用