Changes in the carriage of Campylobacter strains by poultry carcasses during processing in abattoirs

The recent development of simple, rapid genotyping techniques for Campyloba cter species has enabled investigation of the determinative epidemiology of these organisms in a variety of situations. In this study we have used the technique of fla typing (PCR-restriction fragment length polymorphism anal ysis of the flaA and flaB genes) to identify the sources of strains contami nating the carcasses of five campylobacter-positive and two campylobacter-n egative broiler Rocks during abattoir processing. The results confirmed tha t, in the United Kingdom, individual broiler flocks are colonized by a limi ted number of subtypes of Campylobacter jejuni or C, coli, In some but not all cases, the same subtypes, isolated from the ceca, contaminated the end product as observed in carcass washes. However, the culture methodology, i, e, use of direct plating or enrichment, affected this subtype distribution. Moreover, the number of isolates analyzed per sample was limited. fla typi ng also indicated that some campylobacter subtypes survive poultry processi ng better than others. The extent of resistance to the environmental stress es during processing varied between strains. The more robust subtypes appea red to contaminate the abattoir environment, surviving through carcass chil ling, and even carrying over onto subsequent Rocks. From these studies it i s confirmed that some campylobacter-negative flocks reach the abattoir but the carcasses from such Rocks are rapidly contaminated by various campyloba cter subtypes during processing. However, only some of these contaminating subtypes appeared to survive processing. The sources of this contamination are not clear, but in both negative Rocks, campylobacters of the same subty pes as those recovered from the carcasses were isolated from the crates use d to transport the birds. In one case, this crate contamination was shown t o be present before the birds were loaded.