Functionality and safety of lactic bacterial strains from Korean kimchi

The functional characteristics and safety of five different putative probiotic Lactobacillus plantarum strains and one Leuconostoc citreum strain, isolated from kimchi, were studied. In view of their potential application in food biotechnology, this information was considered necessary, and included the determination of antibiotic resistance, haemolysis, gelatinase activity and biogenic amine production. In addition to a Lactobacillus fermentum strain isolated from pig faeces, two commercial probiotic strains (Lactobacillus rhamnosus GG, ATCC 53103, and Lactobacillus plantarum 299v, both originating from the human intestinal track) were included in the studies for reference purposes. With the exception of L. fermentum, which was resistant to a low concentration (MIC: 30 μg/ml) of tetracycline, all strains were susceptible to the 8 antibiotics tested (erythromycin, gentamicin, ampicillin, tetracycline, chloramphenicol, streptomycin, ciprofloxacin, and benzylpenicillin). All strains survived physiological conditions typical of the upper GIT, comprising a pH of 3.0 for 1 h, and a subsequent 2 h under conditions simulating the duodenum, which included the exposure to 10 % of bile salts. Moreover, all strains were resistant to 0.4 % phenol, and were unable to produce any detectable biogenic amines under the test conditions. These preliminary in vitro tests indicate the safety and functionality of the five selected L. plantarum strains and thus their potential as probiotic candidates.