The use of a surface adhesion immunofluorescent (SAIF) method for the rapid detection of Yersinia enterocolitica serotype O:3 in meat

Abstract

This study examined the attachment kinetics of Yersinia enterocolitica serotype O:3 to determine the optimum conditions for its isolation from meat enrichment systems using a novel surface adhesion technique. Minced beef was inoculated with Y. enterocolitica at an initial level of 10 cfu g-1 and incubated at 25 degrees C in an enrichment broth. Yersinia was recovered from enriched samples on polycarbonate membranes by surface adhesion and enumerated using immunofluorescence microscopy. The surface adhesion immunofluorescence technique (SAIF) had a minimum detection limit of approximately 4.0-4.5 log10 cfu ml-1 and provided good correlation between the estimation of the numbers of Yersinia in the enrichment broth derived from plate counts on Yersinia Selective agar (CIN) and those determined by SAIF (r2 = 0.94; rsd = +/- 0.21). A derived regression equation of the SAIF count vs plate counts was used to predict Y. enterocolitica numbers in spiked meat samples stored at 0 degree C for up to 20 d. The numbers as predicted by the SAIF method showed good correlation with counts derived by plating techniques (r2 = 0.78; rsd = +/- 0.42). The application of the SAIF technique for the rapid detection of Y. enterocolitica serotype O:3 from meat is discussed.