Vice Zachariah, Zhou You, Chitlapilly Dass Sapna, Wang Rong
Department of Animal Science, Texas A&M University, College Station, TX 77845, USA.
Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.
Foods. 2025 Jan 15;14(2):268. doi: 10.3390/foods14020268.
represents a diverse group of pathogens commonly associated with food contamination including red meat. Even though pre- and post-harvest cleaning and sanitization procedures are widely implemented at meat processing plants to mitigate the hazard, cells may escape the process by colonizing, on contact, surfaces in the form of a biofilm that functions as an aggregated microbial community to facilitate mutual protection, antimicrobial resistance, proliferation and dissemination. Biofilm development is a complex process that can be affected by a variety of factors including environmental temperature. We developed methods using scanning electron microscopy and confocal microscopy with a novel image analysis software tool to investigate the temperature influence on cell colonization and biofilm formation by directly visualizing and comparing the biofilm matrix's morphological differences under various temperatures. Cocktails of strains belonging to serovars, commonly isolated from meat samples, were applied to develop biofilms on a stainless steel surface at 7, 15, or 37 °C. Results of the microscopy analysis showed that as temperature increased, better-defined biofilm structures with extracellular polymeric structures (EPS) could be identified. However, colonization and aggregated bacterial biomass were clearly observed at the low temperature (7 °C) as well. These results demonstrate that the environmental temperature significantly contributes to biofilm formation as the higher temperatures encourage bacterial active proliferation and biofilm maturation leading to the development of well-pronounced structures, while the lower temperature may promote cell attachment but, meanwhile, limit the EPS biosynthesis and biofilm maturation. Our study indicates that the mature biofilms formed under favorable conditions may protect the pathogens with the well-developed 3-demensional (3D) structure against routine treatment. Furthermore, the low temperatures commonly maintained at meat plants are not able to effectively prevent colonization and biofilm formation since at such temperatures there could still be colonized biomass that can contaminate the products. Therefore, the temperature effect on pathogen colonization and biofilm development should be taken into consideration while evaluating hygiene standards and sanitization procedures at the processing facilities.
代表了一组与包括红肉在内的食品污染相关的多种病原体。尽管肉类加工厂广泛实施收获前和收获后的清洁和消毒程序以减轻危害，但细胞可能通过以生物膜形式定殖在接触的表面上而逃脱该过程，生物膜作为一个聚集的微生物群落发挥作用，以促进相互保护、抗微生物抗性、增殖和传播。生物膜形成是一个复杂的过程，可能受到包括环境温度在内的多种因素的影响。我们开发了使用扫描电子显微镜和共聚焦显微镜以及一种新型图像分析软件工具的方法，通过直接可视化和比较不同温度下生物膜基质的形态差异来研究温度对细胞定殖和生物膜形成的影响。将属于血清型的菌株混合物（通常从肉类样品中分离得到）应用于在不锈钢表面于7、15或37°C下形成生物膜。显微镜分析结果表明，随着温度升高，可以识别出具有更明确的细胞外聚合物结构（EPS）的生物膜结构。然而，在低温（7°C）下也清楚地观察到了细胞定殖和聚集的细菌生物量。这些结果表明，环境温度对生物膜形成有显著影响，因为较高温度促进细菌的活跃增殖和生物膜成熟，导致形成明显的结构，而较低温度可能促进细胞附着，但同时限制EPS生物合成和生物膜成熟。我们的研究表明，在有利条件下形成的成熟生物膜可能通过发育良好的三维（3D）结构保护病原体免受常规处理。此外，肉类加工厂通常维持的低温不能有效防止细胞定殖和生物膜形成，因为在这样的温度下仍然可能存在可污染产品的定殖生物量。因此，在评估加工设施的卫生标准和消毒程序时，应考虑温度对病原体定殖和生物膜发育的影响。
