Rezaei Zeinab, Khanzadi Saeid, Salari Amir
Department of Food Hygiene and Aquaculture, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran.
AMB Express. 2021 Nov 25;11(1):156. doi: 10.1186/s13568-021-01320-7.
Currently, the health benefits of probiotic bacteria are well known, and this has taken up a great deal of space in food science and health, both research and operational. On the other hand, anti-biofilm properties on food pathogens in the food and pharmaceutical industries have created an attractive challenge. This study aimed to describe the inhibitory activity of cell-free supernatants (CFS), planktonic cells, and biofilm form of lactobacilus strains (L. rhamnosus and L. plantarum) against food pathogens such as Pseudomonas aeruginosa and Listeria monocytogenes. Anti-bacterial activities of the CFS of lactobacillus strains were assessed by the microplate method and via violet staining. Evaluation of the antagonistic activity of planktonic cells and biofilm of LAB were performed by the spread plate method. The results showed the incubation time of 48 h was the best time to produce biofilm. Although the planktonic states reduce the pathogens bacterial about 1 -1.5 log, but in biofilm forms, decreased L. monocytogenes about 4.5 log compared to the control, and in the case of P. aeruginosa, a growth reduction of about 2.13 log was observed. Furthermore, biofilm formation of L. monocytogenes in the presence of L. rhamnosus cell-free supernatant was more weakly than L. plantarum CFS, but their CFS effect on reducing the bacterial population of P. aeruginosa was the same. According to the study, biofilm produced by probiotic strains can be considered a new approach for biological control. Also, cell-free supernatant can be used as postbiotic in the food and pharmaceutical industries.
目前，益生菌的健康益处已广为人知，这在食品科学与健康领域的研究及实践中都占据了大量空间。另一方面，其对食品和制药行业中食品病原体的抗生物膜特性带来了一个颇具吸引力的挑战。本研究旨在描述鼠李糖乳杆菌和植物乳杆菌的无细胞上清液（CFS）、浮游细胞及生物膜形式对铜绿假单胞菌和单核细胞增生李斯特菌等食品病原体的抑制活性。通过微孔板法和革兰氏染色评估了乳杆菌菌株CFS的抗菌活性。采用平板涂布法评估了LAB浮游细胞和生物膜的拮抗活性。结果表明，48小时的孵育时间是形成生物膜的最佳时间。尽管浮游状态下病原体细菌数量减少了约1 - 1.5个对数，但在生物膜形式下，与对照组相比，单核细胞增生李斯特菌数量减少了约4.5个对数，对于铜绿假单胞菌，观察到其生长减少了约2.13个对数。此外，在鼠李糖乳杆菌无细胞上清液存在的情况下，单核细胞增生李斯特菌的生物膜形成比植物乳杆菌CFS更弱，但其CFS对减少铜绿假单胞菌细菌数量的效果相同。根据该研究，益生菌菌株产生的生物膜可被视为一种生物控制的新方法。此外，无细胞上清液可用作食品和制药行业的后生元。
