Rapid and sensitive detection techniques for foodborne pathogens are important to the food industry. However, traditional detection methods rely on bacterial culture in combination with biochemical tests, a process that typically takes 4 to 7 days to complete. Thus, this study was conducted to address the issue of time lag inherent in traditional methods by developing a novel PCR assay for each of five foodborne pathogenic bacteria. This new system consists of a simultaneous screening method using multiplex PCR in a single reaction tube for the rapid and sensitive detection of each of the five bacteria. Specific primers for multiplex PCR amplification of the Shiga-like toxin (verotoxin type II), femA (cytoplasmic protein), toxR (transmembrane DNA binding protein), iap (invasive associative protein), and invA (invasion protein A) genes were designed to allow simultaneous detection of Escherichia coli O157:H7, Staphylococcus aureus, Vibrio parahaemolyticus, Listeria monocytogenes, and Salmonella, respectively. To confirm the specificity of each primer pair for the respective target gene, three types of experiments were carried out using boiled cell lysates and their DNAs. In the multiplex PCR with mixed DNA samples, specific bands for corresponding genes were simultaneously detected from a single reaction. The detection of all five foodborne pathogenic bacteria could be completed in less than 24 h with this novel PCR method.

Acne vulgaris is a common chronic skin disorder that affects millions of people. The pathogenesis of acne has been known to be closely associated with the bacterium Propionibacterium acnes. Here we investigated the anti-acne activity of Lactobacillus plantarum K-1 BR by observing the expressions of proinflammatory cytokines, TNF-α, IFN-γ and IL-8, of human keratinocytes. When we applied heat-killed P. acnes to HaCaT cells, the inflammatory cytokines were induced by two-to four-fold compared to the normal control. When the bacteriocin, purified from L. plantarum K-1 BR, was pretreated to the HaCaT cells, the expression levels of TNF-α and IFN-γ stimulated by P. acnes significantly decreased to 25% and 30% of the induced levels, respectively. The IL-8 levels also significantly decreased with the concentration dependent manner of the bacteriocin. These results suggest that the bacteriocin from L. plantarum K-1 BR could reduce the expression levels of inflammatory cytokines and thus may relieve inflammations caused by acne.