A study of the growth of plasmid bearing and plasmid cured strains of antibiotic resistant Yersinia enterocolitica serotype 0 : 3 on refrigerated beef, pork and lamb

The growth of antibiotic-resistant strains of plasmid bearing (P+) and plas mid cured (P-) strains of Yersinia enterocolitica serotype O:3 on minced an d whole pieces of beef, pork and lamb at 0, 5 and 10 degrees C was examined . Yersinia grew on both meat forms and ail species types at most storage te mperatures examined. Similar growth rates were displayed by P+ and P- strai ns of Y. enterocolitica under each temperature and meat form, suggesting th at the virulence plasmid had no significant effect on growth rates, it was noted however, that initial Yersinia growth on pork was slightly faster tha n on beef or lamb although the final numbers observed were slightly lower t han on the other two meat types. The study demonstrated that Yersinia was i nhibited to a greater extent on pork than beef or lamb. This study has prop osed that inhibition may be due to competition from the natural meat microf lora, in particular, the Pseudomonads. (C) 1998 Academic Press.