Hygiene and Food Inspection Unit, Department of Food and Animal Science, Universitat Autònoma de Barcelona, CP 08193 Barcelona, Spain.
Hygiene and Food Inspection Unit, Department of Food and Animal Science, Universitat Autònoma de Barcelona, CP 08193 Barcelona, Spain.
Int J Food Microbiol. 2019 Jan 16;289:209-214. doi: 10.1016/j.ijfoodmicro.2018.10.020. Epub 2018 Oct 25.
The presence of biofilms in food industrial environments is one of the main causes associated with food product contamination by L. monocytogenes. Biofilm control in the food industry is very relevant to public health and finding reliable and realistic quantification methods is essential. The aim of this study is to compare five L. monocytogenes biofilm quantification methods - conventional plate count, TEMPO, DEM, VIDAS and qPCR - and to examine a biodetector to visually detect biofilms in industrial settings. Results show that depending on the biofilm matrix production, the recovery of cells that conform the biofilm can be low and therefore, if it is an indirect method, microbial counts can be underestimated. At a species level, the methods that did not present significant differences were plate count, TEMPO (P = 0.998), DEM and qPCR (P = 0.508), so correlation studies were performed which established high correlation for plate count and TEMPO, but not for DEM and qPCR. The VIDAS method was adjusted so that it could quantify the biofilms, but the standard curve only allowed counts from 7 Log CFU cm. Results also revealed that the different strains of L. monocytogenes possess different biofilm-forming abilities, although it was not possible to correlate the capacity to produce these structures with the distinct serotypes. Last, visually detecting biofilms on stainless steel coupons proved that in industrial environments nowadays they can be rapidly and qualitatively detected so that relevant decisions can immediately be taken.
生物膜在食品工业环境中的存在是与单核细胞增生李斯特菌污染食品产品相关的主要原因之一。在食品工业中控制生物膜对于公共健康非常重要，找到可靠和现实的量化方法至关重要。本研究旨在比较五种单核细胞增生李斯特菌生物膜量化方法——传统平板计数法、TEMPO、DEM、VIDAS 和 qPCR，并研究一种生物探测器，以便在工业环境中直观地检测生物膜。结果表明，取决于生物膜基质的产生，形成生物膜的细胞的回收可能较低，因此，如果是间接方法，微生物计数可能会被低估。在种水平上，没有显著差异的方法是平板计数法、TEMPO（P=0.998）、DEM 和 qPCR（P=0.508），因此进行了相关性研究，结果表明平板计数法和 TEMPO 之间存在高度相关性，但 DEM 和 qPCR 之间没有相关性。对 VIDAS 方法进行了调整，以便能够定量生物膜，但标准曲线仅允许 7 Log CFU cm 的计数。结果还表明，不同的单核细胞增生李斯特菌菌株具有不同的形成生物膜的能力，尽管无法将产生这些结构的能力与不同的血清型相关联。最后，在不锈钢试片上直观地检测生物膜表明，在当今的工业环境中，可以快速定性地检测到它们，以便立即做出相关决策。
