U.S. Food and Drug Administration, Institute for Food Safety and Health, 6502 South Archer Road, Bedford Park, Illinois 60501, USA.
J Food Prot. 2012 Aug;75(8):1382-93. doi: 10.4315/0362-028X.JFP-11-548.
A nationwide survey was conducted to obtain qualitative and quantitative data on bacterial contamination of raw commingled silo milk intended for pasteurization. The levels of total aerobic bacteria, total coliforms, Enterobacteriaceae, Escherichia coli, and Staphylococcus aureus were determined using the TEMPO system. The prevalence rates and levels of presumptive Bacillus cereus, E. coli O157:H7, Listeria monocytogenes, and Salmonella spp. were determined in 214 samples. B. cereus was detected in 8.91% of samples, at 3.0 to 93 CFU/ml. E. coli O157:H7 was detected in 3.79 to 9.05% of samples, at <0.0055 to 1.1 CFU/ml, depending on the assay utilized. Salmonella spp. were recovered from 21.96 to 57.94% of samples, at <0.0055 to 60 CFU/ml. L. monocytogenes was detected in 50.00% of samples, at <0.0055 to 30 CFU/ml. The average log-transformed counts of total viable bacteria were slightly lower in samples containing no pathogens. No correlation was observed between the levels of organisms detected with the TEMPO system and the presence or levels of any pathogen except E. coli O157:H7. A higher average log-transformed count of total viable bacteria was observed in samples positive for this organism. The high prevalence rates of target pathogens may be attributed to a variety of factors, including detection methods, sample size, and commingling of the milk in the silo. The effects of commingling likely contributed to the high prevalence rates and low levels of target pathogens because of the inclusion of milk from multiple bulk tanks. The high prevalence rates also may be the result of analysis of larger sample volumes using more sensitive detection methods. These quantitative data could be utilized to perform more accurate risk assessments and to better estimate the appropriate level of protection for dairy products and processing technologies.
一项全国性调查旨在获取用于巴氏消毒的原始混合青贮牛奶的细菌污染的定性和定量数据。使用 TEMPO 系统测定总需氧菌、总大肠菌群、肠杆菌科、大肠杆菌和金黄色葡萄球菌的水平。在 214 个样本中检测了推定的蜡样芽孢杆菌、O157:H7 型大肠杆菌、单核细胞增生李斯特菌和沙门氏菌的流行率和水平。在 8.91%的样本中检测到蜡样芽孢杆菌，浓度为 3.0 至 93 CFU/ml。根据所使用的检测方法，O157:H7 型大肠杆菌的检出率为 3.79%至 9.05%，浓度为<0.0055 至 1.1 CFU/ml。沙门氏菌从 21.96%至 57.94%的样本中回收，浓度为<0.0055 至 60 CFU/ml。单核细胞增生李斯特菌在 50.00%的样本中检出，浓度为<0.0055 至 30 CFU/ml。在不含病原体的样本中，总活菌的平均对数转换计数略低。除了 O157:H7 型大肠杆菌之外，未观察到 TEMPO 系统检测到的生物体水平与任何病原体的存在或水平之间存在相关性。在检测到这种生物体的样本中，总活菌的平均对数转换计数更高。目标病原体的高流行率可能归因于多种因素，包括检测方法、样本量以及青贮中的混合。由于包括了来自多个大容量罐的牛奶，混合的影响可能导致目标病原体的高流行率和低水平。高流行率也可能是由于使用更敏感的检测方法分析更大的样本量所致。这些定量数据可用于进行更准确的风险评估，并更好地估计乳制品和加工技术的适当保护水平。
