Oscar T P
U.S. Department of Agriculture, Agricultural Research Service, Chemical Residue and Predictive Microbiology Research Unit, Room 2111, Center for Food Science and Technology, University of Maryland Eastern Shore, Princess Anne, Maryland 21853, USA.
J Food Prot. 2014 Jul;77(7):1086-92. doi: 10.4315/0362-028X.JFP-13-505.
Salmonella bacteria that survive cooking or that cross-contaminate other food during meal preparation and serving represent primary routes of consumer exposure to this pathogen from chicken. In the present study, enrichment real-time PCR (qPCR) was used to enumerate Salmonella bacteria that contaminate raw chicken parts at retail or that cross-contaminate cooked chicken during simulated meal preparation and serving. Whole raw chickens obtained at retail were partitioned into wings, breasts, thighs, and drumsticks using a sterilized knife and cutting board, which were then used to partition a cooked chicken breast to assess cross-contamination. After enrichment in buffered peptone water (400 ml, 8 h, 40°C, 80 rpm), subsamples were used for qPCR and cultural isolation of Salmonella. In some experiments, chicken parts were spiked with 0 to 3.6 log of Salmonella Typhimurium var. 5- to generate a standard curve for enumeration by qPCR. Of 10 raw chickens examined, 7 (70%) had one or more parts contaminated with Salmonella. Of 80 raw parts examined, 15 (19%) were contaminated with Salmonella. Of 20 cooked chicken parts examined, 2 (10%) were cross-contaminated with Salmonella. Predominant serotypes identified were Typhimurium (71%) and its variants (var. 5-, monophasic, and nonmotile) and Kentucky (18%). The number of Salmonella bacteria on contaminated parts ranged from one to two per part. Results of this study indicated that retail chicken parts examined were contaminated with low levels of Salmonella, which resulted in low levels of cross-contamination during simulated meal preparation and serving. Thus, if consumers properly handle and prepare the chicken, it should pose no or very low risk of consumer exposure to Salmonella.
在烹饪过程中存活下来的沙门氏菌，或者在餐食准备和供应过程中污染其他食物的沙门氏菌，是消费者通过鸡肉接触这种病原体的主要途径。在本研究中，富集实时荧光定量聚合酶链反应（qPCR）用于对零售时污染生鸡肉部位或在模拟餐食准备和供应过程中污染熟鸡肉的沙门氏菌进行计数。在零售处获得的整只生鸡，用消毒过的刀和案板分割成翅膀、胸脯、大腿和鸡腿，然后用这些部位分割一块熟鸡胸肉以评估交叉污染情况。在缓冲蛋白胨水中富集培养（400毫升，8小时，40℃，80转/分钟）后，取子样本用于沙门氏菌的qPCR检测和培养分离。在一些实验中，向鸡肉部位接种0至3.6个对数的鼠伤寒沙门氏菌变种5 -，以生成用于qPCR计数的标准曲线。在检查的10只生鸡中，7只（70%）有一个或多个部位被沙门氏菌污染。在检查的80个生鸡肉部位中，15个（19%）被沙门氏菌污染。在检查的20个熟鸡肉部位中，2个（10%）被沙门氏菌交叉污染。鉴定出的主要血清型为鼠伤寒沙门氏菌（71%）及其变种（变种5 -、单相和无动力）和肯塔基沙门氏菌（18%）。受污染部位的沙门氏菌数量为每个部位一到两个。本研究结果表明，所检查的零售鸡肉部位被低水平的沙门氏菌污染，这导致在模拟餐食准备和供应过程中交叉污染水平较低。因此，如果消费者正确处理和烹饪鸡肉，那么消费者接触沙门氏菌的风险应该为零或非常低。
