title: Antimicrobial Activity of Kefir against Various Food Pathogens and Spoilage Bacteria.
abstract: Kefir is a unique fermented dairy product produced by a mixture of lactic acid bacteria, acetic acid bacteria, and yeast. Here, we compared the antimicrobial spectra of four types of kefirs (A, L, M, and S) fermented for 24, 36, 48, or 72 h against eight food-borne pathogens.Bacillus cereus,Staphylococcus aureus,Listeria monocytogenes,Enterococcus faecalis,Escherichia coli,Salmonella Enteritidis,Pseudomonas aeruginosa, andCronobacter sakazakiiwere used as test strains, and antibacterial activity was investigated by the spot on lawn method. The spectra, potencies, and onsets of activity varied according to the type of kefir and the fermentation time. The broadest and strongest antimicrobial spectrum was obtained after at least 36-48 h of fermentation for all kefirs, although the traditional fermentation method of kefir is for 18-24 h at 25℃. For kefir A,B. cereus,E. coli,S. Enteritidis,P. aeruginosa, andC. sakazakiiwere inhibited, whileB. cereus,S. aureus,E. coli,S. Enteritidis,P. aeruginosa, andC. sakazakiiwere inhibited to different extents by kefirs L, M, and S. Remarkably,S. aureus,S. Enteritidis, andC. sakazakiiwere only inhibited by kefirs L, M, and S, andL. monocytogenesby kefir M after fermentation for specific times, suggesting that the antimicrobial activity is attributable not only to a low pH but also to antimicrobial substances secreted during the fermentation.
authors.affiliation: Center for One Health, College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea.
authors.forename: Dong-Hyeon
authors.initials: DH
authors.lastname: Kim
authors.affiliation: Center for One Health, College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea.
authors.forename: Dana
authors.initials: D
authors.lastname: Jeong
authors.affiliation: Department of Food & Nutrition, College of Human Ecology, Hanyang University, Seoul 04763, Korea.
authors.forename: Hyunsook
authors.initials: H
authors.lastname: Kim
authors.affiliation: Center for One Health, College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea.
authors.forename: Il-Byeong
authors.initials: IB
authors.lastname: Kang
authors.affiliation: Center for One Health, College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea.
authors.forename: Jung-Whan
authors.initials: JW
authors.lastname: Chon
authors.affiliation: Center for One Health, College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea.
authors.forename: Kwang-Young
authors.initials: KY
authors.lastname: Song
authors.affiliation: Center for One Health, College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea.
authors.forename: Kun-Ho
authors.initials: KH
authors.lastname: Seo
keywords: Kefir; antimicrobial activity; fermentation time; food-borne pathogen; probiotics