University of São Paulo, School of Animal Science and Food Engineering, Department of Food Engineering, Av. Duque de Caxias Norte, 225, CEP 13635-900 Pirassununga, SP, Brazil.
University of São Paulo, College of Agriculture "Luiz de Queiroz", Department of Agro-Industry, Food and Nutrition, CEP 13418-900 Piracicaba, SP, Brazil.
Food Res Int. 2017 Jan;91:88-91. doi: 10.1016/j.foodres.2016.11.039. Epub 2016 Dec 1.
The persistence of Listeria monocytogenes in food industry environments has been associated to the ability of specific isolates to produce biofilms. This study aimed to evaluate the biofilm production of 85 L. monocytogenes strains previously isolated from samples of cheese, brine and the environment of two cheese processing plants located in São Paulo, Brazil. The L. monocytogenes isolates belonged to serotypes 4b, 1/2b and 1/2c, yielded 30 different pulsotypes by pulsed-field gel electrophoresis (PFGE), and were submitted to biofilm-formation assays on polystyrene microplates and stainless steel coupons incubated statically at 35±0.5°C for 48h. All isolates from different sources showed ability to produce biofilms on polystyrene microplates, from which 21 (24.7%) also produced biofilms on stainless steel. Four isolates (4.7%) belonging to four different pulsotypes were classified as strong biofilms-producers on polystyrene microplates, while isolates belonging to four pulsotypes previously evaluated as persistent had weak or moderate ability to produce biofilms on polystyrene microplates. No relationship between the serotypes or pulsotypes and their biofilm-forming ability was observed. This study highlights the high variability in the biofilm production among L. monocytogenes strains collected from cheese and cheese-production environment, also indicating that strong biofilm-formation ability is not a key factor for persistence of specific isolates in cheese processing plants.
单核细胞增生李斯特菌在食品工业环境中的持续存在与其特定分离株产生生物膜的能力有关。本研究旨在评估 85 株单核细胞增生李斯特菌分离株的生物膜生成能力，这些分离株先前从巴西圣保罗两个奶酪加工厂的奶酪、盐水和环境样本中分离得到。单核细胞增生李斯特菌分离株属于血清型 4b、1/2b 和 1/2c，经脉冲场凝胶电泳（PFGE）产生 30 种不同的脉冲型，并用聚苯乙烯微板和不锈钢试片进行生物膜形成试验，在 35±0.5°C 下静态孵育 48h。来自不同来源的所有分离株均显示出在聚苯乙烯微板上生成生物膜的能力，其中 21 株（24.7%）也在不锈钢上生成生物膜。4 株（4.7%）属于 4 种不同脉冲型的分离株被归类为在聚苯乙烯微板上具有强生物膜生成能力的分离株，而先前评估为持久性的 4 种脉冲型的分离株在聚苯乙烯微板上生成生物膜的能力较弱或中等。未观察到血清型或脉冲型与生物膜形成能力之间存在关系。本研究强调了从奶酪和奶酪生产环境中收集的单核细胞增生李斯特菌菌株在生物膜生成方面的高度变异性，同时表明强生物膜形成能力不是特定分离株在奶酪加工厂中持久性的关键因素。
