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Validation of an Improved Isolation and Detection Method for Campylobacter jejuni in Various Foods

Odongo, Rose

Scope and Method of Study:

The Food and Agricultural Products Center (FAPC) method, an improved method for the detection and isolation of Campylobacter in food, was compared to the Food and Drug Administration/Bacteriological Analytical Method (FDA/BAM) method in the recovery of Campylobacter jejuni inoculated in food samples. Beef, chicken skin, milk and ground beef samples were kept at 4°C for 10 days and the effects of enrichment time storage period, blood supplementation of the enrichment broth and detection method on the recovery of Campylobacter inoculated in the food samples were investigated over the storage period. The abilities of the two methods to recover two strains of Campylobacter jejuni ATCC 29428 and 33560, inoculated in the food samples over the storage period were compared.

Findings and Conclusions:

The results from FDA and FAPC methods for detection of Campylobacter jejuni from food samples were found not to be statistically different from each other. Blood supplementation of the enrichment broth had no effect on the recovery of Campylobacter from food in either method. Although the counts of Campylobacter cells recovered after 48 hours of enrichment were higher than those recovered after 24 hours, counts recovered after 24 hours served the purpose of enrichment and thus, there is no need for a 48-hour enrichment period. The growth curves of Campylobacter cultured at 37°C and 42°C demonstrated that it can grow well at either temperature and therefore it is not necessary to grow Campylobacter at 42°C as required by the FDA protocol. One incubation temperature at 37°C was adequate to recover Campylobacter cells from the food matrices tested.