The antimicrobial properties and biogenic amine production of lactic acid bacteria isolated from various fermented food products

摘要

Lactic acid bacteria (LAB) have been isolated from fermented foodstuff and preidentifiedusing API 50 CHL and confirmed by polymerase chain reaction method toinvestigate the protective properties against important foodborne pathogens of theircell-free supernatants (CFS) and neutralized cell-free supernatants (NCFS). The antimicrobialactivity of CFS and NCFS was determined using agar well diffusion assay.Biogenic amine production of LAB strains were also monitored in tyrosine decarboxylasebroth (TDB). The highest and lowest histamine production were obtainedby Pediococcus pentosaceus (155.66 mg/L) and Lactobacillus plantarum (5.96 mg/L),respectively. CFS obtained from LAB isolates showed better antimicrobial effectsagainst pathogens than NCFS. The CFS and NCFS obtained from L. plantarum showeda high antimicrobial effect against S. Paratyphi A with inhibition zone diameter 22.5and 16.5 mm, respectively. The CFS and NCFS of L. raffinolactis showed strong antibacterialactivities against Listeria monocytogenes, with zone diameter 23.5 and24.5 mm.Practical applicationsAntimicrobial activity of cell-free and neutralized cell-free supernatants obtainedfrom LAB strains was evaluated. Biogenic amine production of LAB strains were alsomonitored in tyrosine decarboxylase broth. All LAB isolates had the capacity to producebiogenic amines. Cell-free supernatants obtained from LAB isolates showedbetter antimicrobial effect against pathogens than neutralized cell-free supernatants.Our results showed that cell-free supernatants can be used as a bio-protective agentin the food industry.