Farber J M, Cai Y, Ross W H
Bureau of Microbial Hazards, Health Protection Branch, Health Canada, Ottawa, Ontario, Canada.
Int J Food Microbiol. 1996 Sep;32(1-2):133-44. doi: 10.1016/0168-1605(96)01117-8.
The effects of pH (5.5, 6.5), temperature (4, 7 and 10 degrees C) and carbon dioxide (10, 30, 50, 70 and 90%) on the growth and/or survival of a five strain mixture of Listeria monocytogenes were examined in brain heart infusion broth. All three variables had a major influence on the growth characteristics of the organism. As expected, both the lag time and generation time increased as the CO2 level increased, and as pH and temperature decreased. Growth over a 30-day period was observed at all parameter combinations tested, except at pH 5.5, 4 degrees C in the presence of either 50, 70 or 90% carbon dioxide. Two primary models, the Gompertz and Baranyi equations, were compared for their ability to describe the growth of L. monocytogenes. In general, the Gompertz model predicted both longer lag and shorter generation times, compared to the Baranyi model. The Baranyi model appeared to fit the overall data better than the Gompertz model. However, these differences were often small. Response surface models were developed for predicting the effects and interactions of the three independent variables on the growth and/or survival of L. monocytogenes in the different modified atmospheres. Results demonstrate the importance of strict temperature control for maintaining the advantages of food shelf life extension in enriched carbon dioxide environments. The information obtained in this study could be used as a guide to manufacturers of modified-atmosphere packaged foods, especially when designing products in which this organism may be a concern.
在脑心浸液肉汤中，研究了pH值（5.5、6.5）、温度（4、7和10摄氏度）以及二氧化碳（10%、30%、50%、70%和90%）对单核细胞增生李斯特菌五菌株混合物生长和/或存活的影响。所有这三个变量对该微生物的生长特性都有重大影响。正如预期的那样，随着二氧化碳水平的升高以及pH值和温度的降低，延滞期和世代时间均增加。在所有测试的参数组合下，均观察到了30天内的生长情况，但在pH值为5.5、4摄氏度且存在50%、70%或90%二氧化碳的情况下除外。比较了两个主要模型，即Gompertz方程和Baranyi方程，以描述单核细胞增生李斯特菌的生长能力。总体而言，与Baranyi模型相比，Gompertz模型预测的延滞期更长，世代时间更短。Baranyi模型似乎比Gompertz模型更能拟合总体数据。然而，这些差异通常较小。建立了响应面模型，以预测这三个自变量对不同改良气氛下单核细胞增生李斯特菌生长和/或存活的影响及相互作用。结果表明，在富含二氧化碳的环境中，严格控制温度对于维持延长食品货架期的优势至关重要。本研究中获得的信息可作为改良气氛包装食品制造商的指南，尤其是在设计可能存在该微生物的产品时。
