Fernandes C F, Flick G J, Silva J L, McCaskey T A
Department of Food Science and Technology, Virginia Polytechnic Institute and State University, Blacksburg 24061-0418, USA.
J Food Prot. 1997 Jan;60(1):54-8. doi: 10.4315/0362-028x-60.1.54.
Fresh aquacultured catfish fillets were obtained from three processors using different processing protocols in summer, autumn, winter, and spring and evaluated for microbial quality. Twenty freshly processed fillets were randomly selected and each fillet was placed in a sterile polyethylene bag. The fillets were transported on ice-pack overnight by air immediately after processing. Five fillets were randomly selected for microbial assays. Each fillet was weighed and an equal volume of sterile 0.1% peptone water at 0 to 1 degrees C was added aseptically. The fillet was massaged (or rinsed) for 120 s and the rinse was used to determine microbial quality. Aerobes (incubation at 35 degrees C for 48 h) and psychrotrophs (incubation at 20 degrees C for 96 h) were enumerated using 3M Petrifilm Aerobic Count plates. Escherichia coli (incubation at 35 degrees C for 24 to 48 h) and total coliforms (incubation at 35 degrees C for 24 to 48 h) were enumerated on 3M Petrifilm E. coli Count plates. Staphylococcus aureus counts were determined on Baird-Parker agar (incubation at 35 degrees C for 48 h). Significant differences (P < or = 0.05) in aerobic, psychrotrophic, total coliform, E. coli, and S. aureus counts due to temperature effects during production and variations in processing protocols were observed. E. coli and S. aureus counts were significantly different during the four seasons. E. coli and S. aureus counts were high during summer and low during winter weather. There was a significant difference (P < or = 0.05) in aerobic, psychrotrophic, and total coliform counts among the three processors during warm weather; however, these differences were significantly (P < or = 0.05) reduced in cold weather.
夏季、秋季、冬季和春季，从三家采用不同加工流程的加工厂获取新鲜的养殖鲶鱼片，并对其微生物质量进行评估。随机选取20片刚加工好的鱼片，每片鱼片放入一个无菌聚乙烯袋中。加工后，鱼片立即用冰袋包装空运过夜。随机选取5片鱼片进行微生物检测。称取每片鱼片的重量，无菌添加等体积的0至1摄氏度的0.1%蛋白胨水。将鱼片按摩（或冲洗）120秒，冲洗液用于测定微生物质量。使用3M Petrifilm需氧菌计数平板对需氧菌（35摄氏度培养48小时）和嗜冷菌（20摄氏度培养96小时）进行计数。在3M Petrifilm大肠杆菌计数平板上对大肠杆菌（35摄氏度培养24至48小时）和总大肠菌群（35摄氏度培养24至48小时）进行计数。在Baird-Parker琼脂平板上测定金黄色葡萄球菌数量（35摄氏度培养48小时）。观察到由于生产过程中的温度影响和加工流程的差异，需氧菌、嗜冷菌、总大肠菌群、大肠杆菌和金黄色葡萄球菌数量存在显著差异（P≤0.05）。四个季节中大肠杆菌和金黄色葡萄球菌数量存在显著差异。夏季大肠杆菌和金黄色葡萄球菌数量高，冬季天气时数量低。温暖天气时，三家加工厂的需氧菌、嗜冷菌和总大肠菌群数量存在显著差异（P≤0.05）；然而，在寒冷天气时，这些差异显著减小（P≤0.05）。
