Enumeration and Reduction of Campylobacter jejuni in Poultry and Red Meats

Abstract

This paper compares alternative methods for enumerating Campylobacter jejuni in meat products, the optimal levels of blood supplementation for enrichment recovery of the organism from chicken and ground beef, and means to reduce or eliminate Campylobacters from chicken through organic acid washes or freeze/thaw treatments. Direct plating onto Campy-BAP medium resulted in equivalent or greater recovery of C. jejuni, compared with MPN procedures using two media described in the literature. Subsequent studies employed direct plating, as it was also faster and simpler than the MPN procedures. Enumeration of enrichment cultures from a blood-containing selective enrichment broth indicated that optimal levels of blood supplementation for the recovery of Campylobacters was dependent on the food investigated. Not only did 0% blood supplementation enhance recovery of the organism from inoculated ground beef, but 7% supplementation actually decreased the numbers recovered from this product. The requirement for blood supplementation was reversed when C. jejuni recovery from chickens was assessed. Significant increases were seen when 7% supplementation was employed as compared with either 1 or 0% blood in the enrichment broth. A freeze (−15°C)/thaw treatment of chicken carcasses reduced the numbers of Campylobacter detected by a factor of greater than 100. Finally, 0.5% of either lactic or acetic acid washes of chicken carcasses at 50°C reduced the numbers of C. jejuni present.