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. 2012 Jan;75(1):164-8. doi: 10.4315/0362-028X.JFP-11-248.
Development of models for growth of Salmonella in the chicken food matrix is time-consuming and expensive. The current study was undertaken to examine growth of Salmonella on different anatomical locations of the chicken carcass. The purpose was to determine whether anatomical location should be included as an independent variable in predictive models for chicken. Eleven anatomical locations were studied: skin (wing, breast, drumstick, and thigh), meat surface (wing, breast, drumstick, and thigh), and meat interior (breast, drumstick, and thigh). Background microflora, pH, and growth (lag time, λ; growth rate, μ; and time for a 3-log increase, t(3)) at 30°C for a small inoculum size (0.92 ± 0.30 log per portion) of Salmonella Typhimurium DT104 were examined. Four or six replicate storage trials were conducted per anatomical location (n = 46 growth curves). Portion sizes were 1.12 ± 0.17 g (mean ± standard deviation) for meat and 0.25 ± 0.08 g for skin. A two-phase linear model was used to determine λ and μ. The effect of anatomical location on dependent variables was assessed by one-way analysis of variance. pH values differed (P < 0.001) among anatomical locations, with skin (6.86 ± 0.20). dark meat (6.39 ± 0.20) . white meat (5.97 ± 0.20). Background microflora (4.32 ± 1.66 log per portion) was variable and not affected (P > 0.05) by anatomical location. Likewise, λ (1.90 ± 0.75 h), μ (0.648 ± 0.120 log/h), and t(3) (6.71 ± 0.82 h) at 30°C were not affected (P > 0.05) by anatomical location. Although there were differences in pH among anatomical locations, these differences were not sufficient to affect growth of Salmonella Typhimurium DT104 at 30°C. If this observation holds for other storage conditions and strains, then anatomical location does not need to be included as an independent variable in predictive models for chicken. This would save significant time and money for the predictive microbiologist.
在鸡食基质中生长沙门氏菌的模型的开发既耗时又昂贵。本研究旨在检查沙门氏菌在鸡胴体不同解剖部位的生长情况。目的是确定解剖部位是否应作为鸡预测模型的一个独立变量。研究了 11 个解剖部位：皮肤（翅膀、胸部、鸡腿和大腿）、肉表面（翅膀、胸部、鸡腿和大腿）和肉内部（胸部、鸡腿和大腿）。背景微生物群、pH 值和在 30°C 下接种小剂量（0.92±0.30 对数/份）鼠伤寒沙门氏菌 DT104 的生长（迟滞时间 λ；生长率 μ；和 3 对数增加的时间 t(3)）进行了研究。每个解剖部位进行了 4 或 6 次重复储存试验（n=46 个生长曲线）。肉块大小为 1.12±0.17 g（平均值±标准偏差）用于肉，0.25±0.08 g 用于皮肤。使用两阶段线性模型确定 λ 和 μ。通过单因素方差分析评估解剖部位对因变量的影响。解剖部位之间的 pH 值不同（P<0.001），皮肤（6.86±0.20）。深色肉（6.39±0.20）。白色肉（5.97±0.20）。背景微生物群（4.32±1.66 对数/份）是可变的，不受解剖部位的影响（P>0.05）。同样，30°C 时的 λ（1.90±0.75 h）、μ（0.648±0.120 log/h）和 t(3)（6.71±0.82 h）不受解剖部位的影响（P>0.05）。尽管解剖部位之间的 pH 值存在差异，但这些差异不足以影响 30°C 下鼠伤寒沙门氏菌 DT104 的生长。如果这一观察结果适用于其他储存条件和菌株，那么在鸡的预测模型中，解剖部位不需要作为一个独立变量。这将为预测微生物学家节省大量的时间和金钱。
