Screening of Antibacterial Lactic Acid Bacteria Strains Isolated from Fresh Vegetables in Ho Chi Minh City

Abstract

   Lactic acid bacteria (LAB) play a crucial role in food fermentation and have potential applications as probiotics due to their ability to produce natural antimicrobial compounds. In this study, 91 microbial strains were isolated from four Chinese cabbage, radish, carrot, and chili collected from different markets in Ho Chi Minh City. The results showed that 30 out of 91 strains exhibited antibacterial activity against at least one pathogenic bacterium, with nine strains displaying inhibitory activity against a broad spectrum of pathogens (e.g. Staphylococcus aureus, Bacillus cereus, Pseudomonas aeruginosa, Escherichia coli, and Salmonella enterica). Five strains (OHT2, OTT1, OTT4, OXC2, and OXC3) retained antibacterial activity when cultured in liquid medium. Biochemical and morphological analyses revealed that OTT1, OTT4, OXC2, and OXC3 strains exhibited typical LAB characteristics: Gram-positive rod-shaped bacteria, non-spore-forming, salt-tolerant (> 3% NaCl), and non-b-hemolytic, whereas OHT2 strain was identified as a yeast strain. Results from 16S rRNA sequencing analysis confirmed that the strain OTT1 belonged to Lactiplantibacillus plantarum, OXC3 to Lactiplantibacillus pentosus, OTT4 and OXC2 to Weissella cibaria. The isolated LAB strains demonstrated potential applications in food fermentation, food preservation, and probiotics.