ABSTRACT
AIMS: To screen from pickled vegetables the potential probiotic lactic acid bacteria (LAB) strains with antagonistic activity against Salmonella invasion in host. METHODS AND RESULTS: Probiotic properties including acid and bile tolerance as well as inhibition on pathogenic bacteria were used for screening of LAB strains from pickled vegetables. Two strains, i.e Pediococcus pentosaceus MP12 and Lactobacillus plantarum LAP6, were selected and further assayed for their activities against Salmonella invasion in mouse liver and spleen. For these two LAB strains, strain LAP6 was able to adhere to the mouse intestinal epithelium cells. CONCLUSIONS: In screening of the probiotic strains able to inhibit the Salmonella invasion in host, factors other than the adherence to host intestinal epithelium may contribute some roles. SIGNIFICANCE AND IMPACT OF THE STUDY: Probiotic LAB strains with activity against Salmonella invasion in host could be isolated from vegetable origins. These strains may be used for vegetable processing.
Subject(s)
Food Preservation , Lactobacillaceae/isolation & purification , Probiotics , Salmonella Infections, Animal/diet therapy , Vegetables , Animals , Antibiosis , Bacterial Adhesion , Cells, Cultured , Colony Count, Microbial , Intestinal Mucosa/microbiology , Lactobacillus plantarum/isolation & purification , Liver/microbiology , Mice , Mice, Inbred BALB C , Pediococcus/isolation & purification , Salmonella Infections, Animal/microbiology , Spleen/microbiologyABSTRACT
A method that combined the immunomagnetic separation (IMS) technique and the multiplex polymerase chain reaction (PCR) method (i.e., the IMS-mPCR method) was developed for simultaneous detection of Listreria monocytogenes and Salmonella spp. in food samples. When only the multiplex PCR method was used, it was found that if cell numbers of each of the two target organisms (L. monocytogenes and Salmonella spp.) were above the detection limit, but differed by more than 2 logs-e.g., n x 10(7) to n x 10(4) or n x 10(6) to n x 10(3)--the organism presenting the lower numbers might go undetected. Following the enrichment step with universal preenrichment (UP) broth, if an IMS method using equal quantities of anti-Listeria and anti-Salmonella immunomagnetic beads was performed prior to PCR, both pathogens could be detected unambiguously. Such results could be obtained for target organisms in food samples, such as milk, dairy, and meat products, if similar enrichment and IMS steps were performed prior to PCR.