Redfern J, Verran J
School of Healthcare Science, Manchester Metropolitan University, Manchester, UK.
Lett Appl Microbiol. 2017 Apr;64(4):276-282. doi: 10.1111/lam.12714. Epub 2017 Feb 2.
Listeria monocytogenes is a pathogenic bacterium, with human disease and infection linked to dairy products, seafood, ready-to-eat meat and raw & undercooked meats. Stainless steel is the most common food preparation surface and therefore, it is important to understand how food storage conditions such as surface materials, temperature and relative humidity can affect survival of L. monocytogenes. In this study, survival of L. monocytogenes on stainless steel was investigated at three temperatures (4, 10 and 21°C), each approx. 11, 50 and 85% humidity. Results indicate that the lower the temperature, the more cells were recovered in all three humidity environments, while medium humidity enhances survival, irrespective of temperature. Lower humidity decreases recovery at all temperatures. These data support the guidance noted above that humidity control is important, and that lower humidity environments are less likely to support retention of viable L. monocytogenes on a stainless steel surface.
Understanding survival of potential food-borne pathogens is essential for the safe production and preparation of food. While it has long been 'common knowledge' that relative humidity can affect the growth and survival of micro-organisms, this study systematically describes the survival of L. monocytogenes on stainless steel under varying humidity and temperatures for the first time. The outcomes from this paper will allow those involved with food manufacture and preparation to make informed judgement on environmental conditions relating to humidity control, which is lacking in the food standards guidelines.
单核细胞增生李斯特菌是一种致病菌，人类疾病和感染与乳制品、海鲜、即食肉类以及生肉和未煮熟的肉类有关。不锈钢是最常见的食品加工表面，因此，了解诸如表面材料、温度和相对湿度等食品储存条件如何影响单核细胞增生李斯特菌的存活非常重要。在本研究中，研究了单核细胞增生李斯特菌在不锈钢上于三种温度（4、10和21°C）下的存活情况，每种温度下湿度分别约为11%、50%和85%。结果表明，温度越低，在所有三种湿度环境中回收的细胞越多，而中等湿度可提高存活率，与温度无关。较低的湿度会降低所有温度下的回收率。这些数据支持了上述湿度控制很重要的指导意见，并且较低湿度的环境不太可能支持不锈钢表面存活的单核细胞增生李斯特菌的留存。
了解潜在食源性病原体的存活情况对于食品的安全生产和加工至关重要。虽然长期以来“常识”认为相对湿度会影响微生物的生长和存活，但本研究首次系统地描述了单核细胞增生李斯特菌在不同湿度和温度下在不锈钢上的存活情况。本文的结果将使食品制造和加工相关人员能够对食品标准指南中缺乏的与湿度控制有关的环境条件做出明智的判断。
