Department of Food Science and Human Nutrition, Michigan State University, East Lansing, Michigan 48824, USA.
J Food Prot. 2010 Feb;73(2):372-5. doi: 10.4315/0362-028x-73.2.372.
The internal muscle environment may enhance thermal resistance of bacterial pathogens. Based on the migration of pathogens into whole muscle products during marination, the validity of current thermal inactivation models for whole muscle versus ground products has been questioned. Consequently, the objective of this work was to compare thermal resistance of Salmonella in whole muscle versus ground pork. Irradiated samples of whole and ground pork loin (5.5 to 7.5 g) were exposed to a Salmonella-inoculated (10(8) CFU/ml) marinade (eight serovar cocktail) for 20 min, placed in sterile brass tubes (12.7 mm diameter), sealed, and heated isothermally at 55, 58, 60, 62, or 63 degrees C, and surviving salmonellae were enumerated on Petrifilm aerobic count plates. The thermal lag times and initial bacterial counts were similar for both whole muscle and ground samples (P > 0.05), with all samples having equivalent compositions, inocula, and thermal histories. Heating temperature and physical state of the meat (whole versus ground muscle) affected Salmonella inactivation, with greater thermal resistance observed in whole than in ground muscle (P < 0.05). Assuming log-linear inactivation kinetics, Salmonella was 0.64 to 2.96 times more heat resistant in whole muscle than in ground pork. Therefore, thermal process validations for pork products should also account for the physical state of the product to ensure microbial safety.
肌肉内部环境可能会增强细菌病原体的耐热性。基于腌制过程中病原体向整块肌肉产品中迁移的情况，目前针对整块肌肉和碎肉产品的热失活动力学模型的有效性受到了质疑。因此，本研究的目的是比较整肌肉和碎猪肉中沙门氏菌的耐热性。辐照的整块和碎猪肉里脊肉（5.5 至 7.5 g）样品（5 种血清型混合）用沙门氏菌接种物（10(8) CFU/ml）腌制液（8 种血清型混合）腌制 20 分钟，然后放入无菌铜管（12.7 毫米直径）中，密封，在 55、58、60、62 或 63°C 下等温加热，并在 Petrifilm 需氧计数平板上对存活的沙门氏菌进行计数。整块肌肉和碎肉样品的热滞后时间和初始细菌计数相似（P>0.05），所有样品的组成、接种物和热历史都相同。加热温度和肉的物理状态（整块与碎肉）影响沙门氏菌失活，整块肌肉中的沙门氏菌比碎肉中的更耐热（P<0.05）。假设对数线性失活动力学，整块肌肉中的沙门氏菌比碎猪肉的耐热性高 0.64 至 2.96 倍。因此，猪肉产品的热力验证还应考虑产品的物理状态，以确保微生物安全。
