Department of Food Science and Nutrition, College of Medicine, University of Valladolid, 47005 Valladolid, Spain.
Department of Statistics, University Carlos III de Madrid, 28903 Getafe, Madrid, Spain.
Food Res Int. 2018 Mar;105:952-961. doi: 10.1016/j.foodres.2017.12.033. Epub 2017 Dec 14.
Listeria monocytogenes is a well-known food-borne pathogen and is among the bacteria best adapted to grow at low temperatures. Psychrotrophic spoilage microorganisms present in milk and milk products are primarily in the genus Pseudomonas, and their numbers increase during cold storage leading to deterioration and/or spoilage. The nature of the competition in two- or three-species bacterial systems with L. monocytogenes, L. innocua, and P. fluorescens in skimmed milk at 7 or 14°C was studied. The Baranyi growth model was used to estimate the growth rate and the maximum population density of the three microorganisms for each strain in single cultures or in two- or three-strains co-cultures. The highest Listeria populations were achieved by pure cultures, decreasing in co-culture with P. fluorescens at both temperatures. A modified deterministic logistic model was applied which includes inhibition functions for single cultures, and two- or three-species cultures. A subsequent Bayesian approach was applied for modelling the bacterial interactions. There was not a direct correlation between the growth rate of P. fluorescens and its inhibitory effect on Listeria species. The use of some species from the natural food microflora to inhibit pathogen growth may be an important tool to enhance the safety of refrigerated foods such as milk and dairy products.
单增李斯特菌是一种众所周知的食源性病原体，也是最能适应低温生长的细菌之一。存在于牛奶和奶制品中的低温腐败微生物主要是假单胞菌属，它们的数量在冷藏过程中会增加，导致变质和/或腐败。在 7°C 或 14°C 的脱脂牛奶中，研究了具有单增李斯特菌、无害李斯特菌和荧光假单胞菌的两种或三种细菌系统中的竞争性质。使用 Baranyi 生长模型来估计三种微生物在单培养或两种或三种菌株共培养中的每种菌株的生长率和最大种群密度。在两种温度下，纯培养物中获得的李斯特菌种群最高，与荧光假单胞菌共培养时会减少。应用了一种改进的确定性逻辑模型，该模型包括对单培养物和两种或三种培养物的抑制功能。随后应用贝叶斯方法对细菌相互作用进行建模。荧光假单胞菌的生长率与其对李斯特菌属的抑制作用之间没有直接相关性。利用自然食品微生物区系中的某些物种来抑制病原体的生长可能是增强冷藏食品（如牛奶和奶制品）安全性的重要工具。
