Investigation of organic acid production, antimicrobialactivity and antibiotic resistance of lactic acid bacteria identified from different foods

In this study, lactic acid bacteria (LAB) strains were isolated from totally 29 samples of packed seafood, raw goat milk and cheese. Totally 131 isolates were phenotypically and morphologically characterised using biochemical tests. Later, the isolated LABs were investigated for antibiotic resistant, antagonistic activity and organic acids (acetic, propionic, butyric) production. Lactobacillus isolates were identified as Lb. rhamnosus, Lb. paracasei subsp. paracasei, Lb. brevis, Lb. sunkii, Lb. zeae, Lb. casei while Lactococcus were identified as L. lactis subsp. lactis and cremoris. Leuconostoc was identified as Leu. mesenteroides subsp. mesenteroides, Weissella; W. confusa and W. cibaria. Enterococcus were also named as E. hirae, E. faecalis, E. lactis, E. faecium, E. gallinarum, E. durans, E. casseliflavus, E. thailandicus. Weisella isolates were resistant to vancomycin, tetracycline, rifampicin, penicillin, ampicillin and gentamycin. Enterococcus isolates were resistant to all antibiotics between 100% and 50% while Leuconostoc isolates (100%) were resistant to ampicillin and streptomycin. Lactobacillus isolates were 100% resistant to ampicillin antibiotic. Acetic acid production was 656.93, 628.96, 503.18, 462.19 330.09, 298.48 and 276.88 mg/L by Weisella, Leuconostoc, Lactococcus, Lactobacillus, Enterococcus spp., Streptococcus and Pediococcus sp., respectively. Butyric acid production by Lactobacillus, Enterococcus and Weisella spp. was 22.00, 11.66 and 11.04 mg/L while propionic acid formation was found to be 42.36, 20.36 and 20.25 mg/L by Leuconostoc spp. Enterococcus spp. and Lactococcus, respectively. LAB strains mostly showed antagonistic activity on Listeria monocytogenes, Pseudomonas aeruginosa, Staphylococcus aureus and Salmonella Paratyphi A as well as Klebsiella pneumonia, Campylobacter jejuni, E.coli and Bacillus subtilis. Key words: LAB strains, Molecular Identification, Antimicrobial activity, Organic acid, Antibiotic resistance.