Microbial Food Safety Research Unit, Eastern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, 600 E. Mermaid Lane, Wyndmoor, PA 19038, USA.
Food Microbiol. 2011 May;28(3):350-5. doi: 10.1016/j.fm.2010.03.004. Epub 2010 Mar 17.
This study examined the growth characteristics of Listeria monocytogenes as affected by a native microflora in cooked ham at refrigerated and abuse temperatures. A five-strain mixture of L. monocytogenes and a native microflora, consisting of Brochothrix spp., isolated from cooked meat were inoculated alone (monocultured) or co-inoculated (co-cultured) onto cooked ham slices. The growth characteristics, lag phase duration (LPD, h), growth rate (GR, log(10) cfu/h), and maximum population density (MPD, log(10) cfu/g), of L. monocytogenes and the native microflora in vacuum-packed ham slices stored at 4, 6, 8, 10, and 12 °C for up to 5 weeks were determined. At 4-12 °C, the LPDs of co-cultured L. monocytogenes were not significantly different from those of monocultured L. monocytogenes in ham, indicating the LPDs of L. monocytogenes at 4-12 °C were not influenced by the presence of the native microflora. At 4-8 °C, the GRs of co-cultured L. monocytogenes (0.0114-0.0130 log(10) cfu/h) were statistically but marginally lower than those of monocultured L. monocytogenes (0.0132-0.0145 log(10) cfu/h), indicating the GRs of L. monocytogenes at 4-8 °C were reduced by the presence of the native microflora. The GRs of L. monocytogenes were reduced by 8-7% with the presence of the native microflora at 4-8 °C, whereas there was less influence of the native microflora on the GRs of L. monocytogenes at 10 and 12 °C. The MPDs of L. monocytogenes at 4-8 °C were also reduced by the presence of the native microflora. Data from this study provide additional information regarding the growth suppression of L. monocytogenes by the native microflora for assessing the survival and growth of L. monocytogenes in ready-to-eat meat products.
本研究考察了冷藏和滥用温度下原生菌群对单核细胞增生李斯特菌在熟火腿中生长特性的影响。将由源自熟肉的布罗特希氏菌组成的五株单核细胞增生李斯特菌和原生菌群混合物单独（纯培养）或共同（共培养）接种到熟火腿片中。在 4、6、8、10 和 12°C 下真空包装的火腿片中，确定了单核细胞增生李斯特菌和原生菌群的生长特性、延迟期持续时间（LPD，h）、生长率（GR，log(10)cfu/h）和最大种群密度（MPD，log(10)cfu/g），并持续 5 周。在 4-12°C 下，共培养单核细胞增生李斯特菌的 LPD 与单核细胞增生李斯特菌在火腿中的 LPD 没有显著差异，表明单核细胞增生李斯特菌在 4-12°C 时的 LPD 不受原生菌群的影响。在 4-8°C 下，共培养单核细胞增生李斯特菌（0.0114-0.0130 log(10)cfu/h）的 GR 略低于单核细胞增生李斯特菌（0.0132-0.0145 log(10)cfu/h），表明在 4-8°C 下，原生菌群降低了单核细胞增生李斯特菌的 GR。在 4-8°C 下，原生菌群使单核细胞增生李斯特菌的 GR 降低了 8-7%，而在 10 和 12°C 下，原生菌群对单核细胞增生李斯特菌的 GR 影响较小。在 4-8°C 下，单核细胞增生李斯特菌的 MPD 也因原生菌群的存在而降低。本研究提供了有关原生菌群抑制单核细胞增生李斯特菌生长的更多信息，用于评估单核细胞增生李斯特菌在即食肉类产品中的存活和生长。
