Title: Yersinia enterocolitica: detection and isolation from food Author
Submitted to: Encyclopedia of Food Microbiology
Publication Type: Book / Chapter
Publication Acceptance Date: October 1, 2012
Publication Date: N/A
Technical Abstract: The detection of plasmid-bearing (pYV) human pathogenic strains of Yersinia enterocolitica depends on the expression of various pYV-associated virulence characteristics. However, diagnostic techniques based on pYV encoded phenotypes have limited reliability due to the unstable nature of pYV. Two rapid, reliable, and simple methods based on the binding of crystal violet and Congo red (CR) uptake for identification of pathogenic pYV-bearing Y. enterocolitica (YEP+) strains are discussed. The CR binding technique allowed both detection and recovery of YEP+ strains. The advantage of swabbing a food surface for selective enrichment of YEP+ serotypes from different food sources is discussed. The YEP+ strains representing five serotypes were simultaneously detected and isolated from enriched swab samples of artificially contaminated pork chops, ground pork, cheese, and zucchini using the CR binding technique. The method was also effective in isolating YEP+ strains from naturally contaminated porcine tongues. Virulence of the strains isolated from these foods was confirmed by PCR, the expression of pYV-associated phenotypes, and mouse pathogenicity. This method of enrichment, detection and isolation is also applicable to frozen food samples artificially contaminated with YEP+ strains at a low to moderate level.