Gill C O, Dussault F, Holley R A, Houde A, Jones T, Rheault N, Rosales A, Quessy S
Agriculture and Agri-Food Canada Research Centre, Lacombe, Alberta.
Int J Food Microbiol. 2000 Jun 30;58(1-2):65-72. doi: 10.1016/s0168-1605(00)00294-4.
The hygienic performances of the processes for the production of cooled carcasses at eight pork packing plants were assessed from small sets of microbiological data. At each plant, a single sample was obtained from a randomly selected site on each of 25 randomly selected carcasses at each of three stages of processing, which were after polishing, after washing at the end of the dressing process, and after cooling. The aerobic bacteria, coliforms and Escherichia coli recovered from each sample were enumerated. When bacteria of one type were recovered from > or = 20 of 25 samples, the log mean number of those bacteria on the population of carcasses undergoing processing was estimated on the assumption that the set of counts was normally distributed. The log of the total number recovered from 25 samples was calculated for each set of counts. The log mean numbers of total aerobic bacteria recovered from the polished carcasses at different plants ranged from about 1.9 to 3.8 log cfu cm(-2). At six of the plants, the log mean numbers of total aerobes on the cooled carcasses did not differ substantially from the log mean numbers on the polished carcasses, but the log mean numbers on the cooled carcasses were substantially higher at one plant and substantially lower at another than on the polished carcasses. Coliforms and E. coli were recovered from too few samples in most sets from cooled carcasses for estimation of their log mean numbers. However, the log total numbers of coliforms and E. coli recovered indicated that substantial numbers of those organisms were added to carcasses during the dressing processes at four of the plants, and that the numbers on the carcasses were substantially reduced by the processes for cooling without spraying at two of the plants. At seven of the plants, the total numbers of coliforms and E. coli recovered from cooled carcasses were <3.1 and <2.2 log cfu 2500 cm(-2), respectively. The findings indicate that production processes for pig carcasses can be operated to give cooled carcasses with log mean numbers of total aerobes < 2 cm(-2), and log total numbers of coliforms and E. coli each < 1 2500 cm(-2).
通过少量微生物数据对8家猪肉加工厂冷却胴体生产过程的卫生性能进行了评估。在每家工厂，在加工的三个阶段，即抛光后、屠宰过程结束时洗涤后以及冷却后，从25头随机选择的胴体上的随机选定部位各获取一个样本。对每个样本中分离出的需氧菌、大肠菌群和大肠杆菌进行计数。当在25个样本中有20个或更多样本分离出某一种细菌时，假设计数集呈正态分布，估算正在加工的胴体群体上该种细菌的对数平均数。计算每组计数中从25个样本中分离出的细菌总数的对数。不同工厂抛光胴体上分离出的需氧菌总数的对数平均数在约1.9至3.8 log cfu cm(-2)之间。在6家工厂，冷却胴体上需氧菌总数的对数平均数与抛光胴体上的对数平均数相比没有显著差异，但在一家工厂冷却胴体上的对数平均数显著高于抛光胴体，而在另一家工厂则显著低于抛光胴体。在冷却胴体的大多数样本组中，分离出的大肠菌群和大肠杆菌数量太少，无法估算其对数平均数。然而，分离出的大肠菌群和大肠杆菌的对数总数表明，在4家工厂的屠宰过程中，大量此类微生物被添加到胴体上，并且在2家不进行喷淋冷却的工厂中，胴体上的此类微生物数量大幅减少。在7家工厂，冷却胴体上分离出的大肠菌群和大肠杆菌总数分别<3.1和<2.2 log cfu 2500 cm(-2)。研究结果表明，猪胴体的生产过程可以控制在使冷却胴体的需氧菌总数对数平均数<2 cm(-2)，大肠菌群和大肠杆菌的对数总数均<1 2500 cm(-2)。
