Gill C O, McGinnis J C, Badoni M
Agriculture and Agri-Food Canada Research Centre, Lacombe, Alberta, Canada.
Int J Food Microbiol. 1996 Aug;31(1-3):181-96. doi: 10.1016/0168-1605(96)00982-8.
Swab samples were obtained from 3 sites on the surfaces of beef carcasses passing through a high speed dressing process, with 24 samples from each site being obtained at each of 4 points in the process. The aerobic microflora recovered from each swab after incubation at 25 degrees C was enumerated and characterized, and numbers of coliforms and Escherichia coli were determined. The data on aerobic flora indicated that skinning results in similar contamination of all 3 sites, that further deposition of bacteria at the brisket site occurs after skinning, and that trimming and washing achieve modest decontamination of the neck and brisket site, and extensive decontamination of the rump site. Changes in flora compositions during processing were too limited to much affect the assessment based on the aerobic flora total counts alone. The E. coli data indicated that during skinning the rump site was more heavily contaminated with faecal organisms than the other sites, that contamination of the brisket site is little altered between skinning and carcass splitting, although there is an extensive redistribution of E. coli at the neck site and sporadic, limited decontamination of the rump site, and that trimming and washing do not decontaminate the neck or rump sites, but that the rump site is extensively decontaminated by trimming. There was good correlation between E. coli and coliform counts, but weak correlation between E. coli and aerobic, 25 degrees C, counts. The findings suggest that assessments of beef carcass dressing processes for Hazard Analysis: Critical Control Point (HACCP) purposes should be based on enumerations of E. coli, or perhaps coliforms, rather than of the aerobic flora, to avoid important misunderstandings of the hygienic effects of the various operations in a process.
在经过高速屠宰处理的牛胴体表面的3个部位采集拭子样本，在该处理过程的4个时间点，每个部位各采集24个样本。将在25℃下培养后从每个拭子中回收的需氧微生物进行计数和鉴定，并测定大肠菌群和大肠杆菌的数量。需氧菌群的数据表明，剥皮会导致所有3个部位受到类似程度的污染，剥皮后胸部部位会有细菌进一步沉积，修整和清洗可使颈部和胸部部位实现适度去污，而臀部部位可实现广泛去污。加工过程中菌群组成的变化非常有限，不足以仅基于需氧菌群总数的评估产生太大影响。大肠杆菌的数据表明，在剥皮过程中，臀部部位比其他部位受到粪便微生物的污染更严重，在剥皮和胴体分割之间，胸部部位的污染变化不大，尽管颈部部位的大肠杆菌有广泛重新分布，且臀部部位有零星、有限的去污，并且修整和清洗不会使颈部或臀部部位去污，但臀部部位通过修整可实现广泛去污。大肠杆菌和大肠菌群计数之间存在良好相关性，但大肠杆菌与25℃下的需氧菌计数之间相关性较弱。研究结果表明，为危害分析关键控制点（HACCP）目的而对牛胴体屠宰过程进行评估时，应基于大肠杆菌或可能的大肠菌群计数，而非需氧菌群计数，以避免对过程中各种操作的卫生效果产生重大误解。
