Hardin M D, Acuff G R, Lucia L M, Oman J S, Savell J W
Institute of Food Science and Engineering, Center for Food Safety, Animal Science Department, Texas A&M University, College Station, Texas 77843-2471.
J Food Prot. 1995 Apr;58(4):368-374. doi: 10.4315/0362-028X-58.4.368.
Methods for the removal of fecal contamination from beef carcass surfaces were evaluated using a fecal suspension containing a rifampicin-resistant strain of either Escherichia coli O157:H7 or Salmonella typhimurium . Paired cuts from four distinct beef carcass regions (inside round, outside round, brisket, and clod) were removed from hot carcasses after splitting, and subcutaneous fat and lean carcass surfaces from these cuts were used to model decontamination of prechilled carcass surface regions. Hot carcass surface regions were contaminated with an inoculated fecal suspension in a 400-cm area and then treated by one of four treatments either immediately or 20 to 30 min after contamination. One paired contaminated surface region from each carcass side was trimmed of all visible fecal contamination. The remaining paired carcass surface region was washed either with water (35°C) or with water followed by a 2% lactic or acetic acid spray (55°C). Surface samples were obtained for microbiological examination before and after treatment from within and outside the defined area contaminated with the fecal suspension. All treatments significantly reduced levels of pathogens; however, decontamination was significantly affected by carcass surface region. The inside round region was the most difficult carcass surface to decontaminate, regardless of treatment. Washing followed by organic acid treatment performed better than trimming or washing alone on all carcass region surfaces except the inside round, where organic acid treatments and trimming performed equally well. Overall, lactic acid reduced levels of E. coli O157:H7 significantly better than acetic acid; however, differences between the abilities of the acids to reduce Salmonella were less pronounced. All treatments caused minimal spread of pathogens outside the initial area of fecal contamination, and recovery after spreading was reduced by organic acid treatments.
使用含有耐利福平的大肠杆菌O157:H7或鼠伤寒沙门氏菌菌株的粪便悬液，评估从牛肉胴体表面去除粪便污染的方法。在分割后从热胴体上取下来自四个不同牛肉胴体区域（内圆、外圆、胸肉和颈肉）的成对肉块，这些肉块的皮下脂肪和瘦肉胴体表面用于模拟预冷胴体表面区域的去污处理。热胴体表面区域在400平方厘米的面积内接种粪便悬液进行污染，然后在污染后立即或20至30分钟后采用四种处理方法之一进行处理。每个胴体侧面的一对受污染表面区域去除所有可见的粪便污染。其余成对的胴体表面区域用水（35°C）清洗或用水清洗后再喷洒2%的乳酸或醋酸（55°C）。在处理前后，从受粪便悬液污染的限定区域内外获取表面样本进行微生物检查。所有处理均显著降低了病原体水平；然而，去污效果受胴体表面区域的显著影响。无论采用何种处理方法，内圆区域都是最难去污的胴体表面。除内圆区域外，在所有胴体区域表面，水洗后进行有机酸处理的效果优于单独修剪或水洗，在内圆区域，有机酸处理和修剪的效果相当。总体而言，乳酸降低大肠杆菌O157:H7水平的效果明显优于醋酸；然而，两种酸降低沙门氏菌能力的差异不太明显。所有处理导致病原体在粪便污染初始区域外的扩散最小，并且有机酸处理降低了扩散后的回收率。
