Survival of Campylobacter jejuni in Frozen Chicken Meat and Genetic Analysis of Isolates by Pulsed-Field Gel Electrophoresis
2005 Volume 22 Issue 2 Pages 59-65
Details
2005 Volume 22 Issue 2 Pages 59-65
Campylobacter jejuni was isolated from 49 of 100 samples (49.0%) of retail chicken. An MPN procedure was used to determine the change in the level of Campylobacter jejuni in chicken meat on freezing. After freezing at-20° for 7 days, bacterial numbers were reduced a factor of 1/10-1/100, and in 25 out of 49 samples (51.0%) numbers decreased to less than the detection limit (<15/100g) for the MPN method.
PFGE analysis of isolates indicated that individual commercial chickens were contaminated with strains of multiple genotypes. In 8 of 24 samples (33.3%), different genotypes were observed among isolates from chicken samples before and after freezing. It is therefore necessary to submit as many isolates for genotyping as possible when investigating the cause of food poisoning.
When studying chickens inoculated with C. jejuni, there was a smaller decrease in bacterial numbers in samples that were kept frozen without thawing than in samples which were repeatedly frozen and thawed. This suggests that the elimination of C. jejuni in frozen chicken mainly occurred during the process of freezing or of thawing.
