Department of Food Science and Nutrition, Faculty of Food Engineering, University of Campinas, Campinas, SP, Brazil.
Department of Food Science and Nutrition, Faculty of Food Engineering, University of Campinas, Campinas, SP, Brazil.
Sci Total Environ. 2022 Oct 15;843:157033. doi: 10.1016/j.scitotenv.2022.157033. Epub 2022 Jun 28.
Listeria monocytogenes of varied sources including food-related sources may reach the soil. Associated food safety and environmental health risks of such contamination depend significantly on the capacity of L. monocytogenes to survive in the soil. This study assessed the survival of 13 L. monocytogenes strains isolated from food and food processing environments and a cocktail of three of the strains in two types of soils (loam and sandy) under controlled temperature conditions: 5, 10, 20, 25, 30℃ and 'uncontrolled' ambient temperature conditions in a tropical region. The impact of compost amendment on the survival of L. monocytogenes in the two different types of soils was also assessed. Soil type, temperature and compost amendment significantly (P <0.001) impacted the survival of L. monocytogenes in soil. Temperature variations affected the survival of L. monocytogenes in soil, where some strains such as strain 732, a L. monocytogenes 1/2a strain survived better at lower temperature (5°C), for which counts of up to 10.47 ± 0.005 log CFU/g were recovered in compost-amended sandy soil, 60 days post-inoculation. Some other strains such as strain 441, a L. monocytogenes 1/2a survived best at intermediate temperature (25 and 30 °C), while others such as 2739 (L. monocytogenes 1/2b) thrived at higher temperature (between 30 °C - 37 °C). There were significant correlations between the influence of temperature and soil type, where lower temperature conditions (5°C - 20°C) were generally more suitable for survival in sandy soil compared to higher temperature conditions. For some of the strains that thrived better in sandy soil at lower temperature, Pearson correlation analysis found significant correlations between temperature and soil type. Steady, controlled temperature generally favored the survival of the strains compared to uncontrolled ambient temperature conditions, except for the cocktail. The cocktail persisted until the last day of post-inoculation storage (60th day) in all test soils and under all incubation temperature conditions. Loam soil was more favorable for the survival of L. monocytogenes and compost amendment improved the survival of the strains, especially in compost-amended sandy soil. Listeria monocytogenes may exhibit variable survival capacity in soil, depending on conditions such as soil type, compost amendment and temperature.
来自食品相关来源的各种来源的单增李斯特菌可能会到达土壤中。这种污染与食品安全和环境卫生风险相关，其严重程度主要取决于单增李斯特菌在土壤中的生存能力。本研究评估了从食品和食品加工环境中分离的 13 株单增李斯特菌菌株以及三种菌株混合物在两种土壤（壤土和沙土）中的存活情况，这两种土壤在受控温度条件下（5、10、20、25、30℃）和热带地区的“非受控”环境温度条件下。还评估了堆肥改良对两种不同类型土壤中单增李斯特菌存活的影响。土壤类型、温度和堆肥改良对土壤中单增李斯特菌的存活有显著影响（P <0.001）。温度变化影响了土壤中单增李斯特菌的存活，一些菌株，如菌株 732（单增李斯特菌 1/2a 菌株）在较低温度（5°C）下生存得更好，在接种后 60 天，在添加堆肥的沙土中可回收高达 10.47 ± 0.005 log CFU/g 的数量。其他一些菌株，如菌株 441（单增李斯特菌 1/2a 菌株）在中等温度（25 和 30°C）下生存得最好，而其他菌株，如 2739（单增李斯特菌 1/2b 菌株）则在较高温度（30°C-37°C）下生长得更好。温度和土壤类型之间存在显著相关性，较低温度（5°C-20°C）条件通常更适合在沙土中生存。对于一些在较低温度下在沙土中生存得更好的菌株，皮尔逊相关分析发现温度和土壤类型之间存在显著相关性。与非受控环境温度条件相比，稳定、受控的温度通常更有利于菌株的存活，除了鸡尾酒。在所有测试土壤和所有孵育温度条件下，鸡尾酒在接种后储存的最后一天（第 60 天）仍然存在。壤土更有利于单增李斯特菌的存活，堆肥改良提高了菌株的存活率，特别是在添加堆肥的沙土中。单增李斯特菌在土壤中的存活能力可能会根据土壤类型、堆肥改良和温度等条件而有所不同。
