In
order to use lactic acid bacteria as starter and non-starter cultures in
fermentative products, their safety qualities should be evaluated. The
objective of the present study was to evaluate safety characteristics including
antibiotic sensitivity pattern, antimicrobial effect, H2O2
production, and biogenic amine production by Lactobacillus plantarum
strains isolated from Siahmazgi cheese. Lactobacillus plantarum strains
were unable to produce tyramine except for SD6 strain. All strains in the
current study were able to produce histamine but unable to decarboxylate
neither lysine nor ornithine. Lactobacillus plantarum strains showed
considerable antimicrobial activity against Salmonella typhimurium and Listeria
monocytogenes. All L. plantarum strains showed stronger
antimicrobial activity against S. typhimurium (3.5-42.55 mm) than L.
monocytogenes (1.5-30.49 mm). The SC9 strain had the strongest inhibitory
effect against both pathogens. After titering pH of the medium to approximately
6.5, no antimicrobial activity was noticed indicating that the antimicrobial
activity of L. plantarum strains was contributed to their acid
production and not to bacteriocin. All L. plantarum strains were capable
of producing H2O2. SA32 and SD13 strains with 2.37 and
0.77 mmol/L were the strongest and the weakest strains regarding H2O2
production, respectively (P˂ 0.05). All L. plantarum strains were
sensitive to chloramphenicol, erythromycin, rifampicin, and tetracycline, yet
resistant against vancomycin, and norfloxacin. Four patterns of antibiotic
resistance were observed among L. plantarum strains. Only two strains of
SC9 and SE4 were resistant against four antibiotics. L. plantarum
strains naturally found in Siahmazgi cheese do not generally possess dangerous
characteristics to be used in fermentative dairy products.
Primary Language | English |
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Subjects | Veterinary Surgery |
Journal Section | Articles |
Authors | |
Publication Date | September 9, 2019 |
Published in Issue | Year 2019 |