ENTEROTOXIN PRODUCTION BY YERSINIA SPECIES AT 4 AND 25 C

Abstract

Yersinia cntcrocolitica is new included in the classification of both the invasive bacteria (e.g. Shigella) and the toxicogenic bacteria (e.g. Escherichia coli). three human strains and 43 environmental strains were used to produce Y. enteroclitica enterotoxin at 4 C , 25'C and 37 C using infant mouse assay. At 25 C enterotoxin was produced by 10 environmental strains and by all of the 3 human strains. Enterotoxin was produced by only 3 environmental strains (yersinia intermedia) at 4 C. At 37"C, none of the strains protluced enterotoxin. This enterotoxin was stable for 2 months at 4"C andjor 6 months at 60°C. At 100°C for 10 to 60 minutes and 121 C (autoclave) for 20 minutes this enterotoxin did not loss its activity. the results indicate that Y. intermedia may cause food intoxication after food storage at 4 C temperature.