Physics and Physical Chemistry of Foods, Wageningen University, Wageningen 6708WG, the Netherlands; Food Microbiology, Wageningen University, Wageningen 6708WG, the Netherlands.
Environmental Technology, Wageningen University, Wageningen 6708WG, the Netherlands.
Microbiol Res. 2024 Jun;283:127674. doi: 10.1016/j.micres.2024.127674. Epub 2024 Mar 5.
The role of lactic acid bacteria, including Lactiplantibacillus plantarum, in food spoilage is well recognized, while the behavior of these non-motile bacteria on wet surfaces, such as those encountered in food processing environments has gained relatively little attention. Here, we observed a fast colony spreading of non-motile L. plantarum spoilage isolates on wet surfaces via passive sliding using solid BHI agar media as a model. We investigated the effect of physical properties of agar hydrogel substrate on the surface spreading of six L. plantarum food isolates FBR1-6 and a model strain WCFS1, using increasing concentrations of agar from 0.25 up to 1.5% (w/v). Our results revealed that L. plantarum strain FBR2 spreads significantly on low agar concentration plates compared to the other strains studied here (with a factor of 50-60 folds higher surface coverage), due to the formation of very soft biofilms with high water content that can float on the surface. The fast-spreading of FBR2 colonies is accompanied by an increased number of cells, elongated cell morphology, and a higher amount of extracellular components. Our finding highlights colonization dynamics and the spreading capacity of non-motile bacteria on surfaces that are relatively wet, thereby revealing an additional hitherto unnoticed parameter for non-motile bacteria that may contribute to contamination of foods by fast surface spreading of these bacteria in food processing environments.
乳酸菌（包括植物乳杆菌）在食物腐败中的作用是众所周知的，而这些非运动性细菌在潮湿表面（如食品加工环境中遇到的表面）上的行为却相对较少受到关注。在这里，我们通过使用固体 BHI 琼脂培养基作为模型，观察到非运动性植物乳杆菌腐败分离株在潮湿表面上通过被动滑动快速形成菌落。我们研究了琼脂水凝胶基质的物理性质对 6 株植物乳杆菌食品分离株 FBR1-6 和模型菌株 WCFS1 在表面扩散的影响，琼脂浓度从 0.25%增加到 1.5%（w/v）。我们的结果表明，与这里研究的其他菌株相比，植物乳杆菌 FBR2 株在低琼脂浓度平板上的扩散明显（表面覆盖率高 50-60 倍），这是由于形成了非常柔软、含水量高的生物膜，可以在表面漂浮。FBR2 菌落的快速扩散伴随着细胞数量的增加、细胞形态的伸长和细胞外成分的增加。我们的发现强调了非运动性细菌在相对潮湿的表面上的定殖动态和扩散能力，从而揭示了一个新的、迄今为止未被注意到的非运动性细菌参数，该参数可能有助于这些细菌在食品加工环境中快速表面扩散而污染食品。
