title: Growth inhibition of foodborne and pathogenic bacteria by conjugated linoleic acid.
abstract: The influence of conjugated linoleic acid (CLA) on the growth of some foodborne and pathogenic bacteria was examined. A potassium salt of CLA (CLA-K) was tested against three Gram-positive strains ( Bacillus cereus , Staphylococcus aureus , and Streptococcus mutans ) and five Gram-negative strains ( Pseudomonas aeruginosa , Salmonella typhimurium , Vibrio parahemolyticus , Klebsiella pneumoniae , and Proteus mirabilis ). CLA-K-mediated growth inhibition was evident for all tested strains, particularly the Gram-positive strains. The IC(50) value of CLA-K was 0.3 mM for B. cereus, 1.2 mM for S. aureus, and 0.3 mM for S. mutans, whereas the value was 1.2 mM for K. pneumoniae, 1.2 mM for P. aeruginosa, 1.8 mM for S. typhimurium, 1.8 mM for V. parahemolyticus, and 2.4 mM for P. mirabilis. The CLA-K delayed the growth of all the tested strains at lower CLA-K concentrations, but completely inhibited the growth at higher concentrations. All cells grown in the medium containing CLA-K contained CLA in their membranes and exhibited irregular cell surface and cell disruption, which were greater in Gram-positive than Gram-negative strains. Higher lactic dehydrogenase activity (LDH), protein content, and malondialdehyde (MDA) content were evident in Gram-positive strains than in Gram-negative strains. These results suggest that the broad spectrum of growth inhibition by CLA mediated through the lipid peroxidation of CLA in the membranes and in the medium.
authors.affiliation: Department of Biomaterial Technology, Gyeongsang National University, Jinju 660-701, Republic of Korea.
authors.forename: Jae Il
authors.initials: JI
authors.lastname: Byeon
authors.forename: Han Suep
authors.initials: HS
authors.lastname: Song
authors.forename: Tae Woo
authors.initials: TW
authors.lastname: Oh
authors.forename: Young Suk
authors.initials: YS
authors.lastname: Kim
authors.forename: Byeong Dae
authors.initials: BD
authors.lastname: Choi
authors.forename: Hong Chul
authors.initials: HC
authors.lastname: Kim
authors.forename: Jeong Ok
authors.initials: JO
authors.lastname: Kim
authors.forename: Ki Hwan
authors.initials: KH
authors.lastname: Shim
authors.forename: Yeong Lae
authors.initials: YL
authors.lastname: Ha