Microbial ecology on poultry carcasses along the production line

In this study we analysed the microflora of chicken feces during the fattening period and the flora on the carcasses at the main slaughter processing steps, using traditional cultural microbiological techniques. There was no relation between composition and concentration of contaminant (enteric) bacteria in feces and on eviscerated carcasses. No significant changes of concentrations of Enterobacteriaceae, E. coli, Enterococci, Staphylococci, Lactobacilli and Pseudomonas were observed after scalding, defeathering and evisceration, whereas during chilling the average counts decreased for >= 0.9 log for all bacterial groups except Staphylococci. None of these bacterial groups was found suitable as an indicator for the contamination of the carcass with bacteria originating from feces, feathers or skin. Pooled fecal samples were taken from flocks in weekly intervals during the entire fattening period and subsequently tested for Salmonella and Campylobacter. The presence of these pathogens in feces [always resulting in carcasses being contaminated (i. e. ca. 18 % for Salmonella and 85 % for Campylobacter)], proved to be unsuitable as a useful predictor, as "false negative" rates were 62.5 % for Salmonella and 25 % for Campylobacter. It is suggested that the above mentioned limitations can be overcome by novel techniques profiling microbial DNA rather than by classical microbiology determining bacterial numbers at genus or species level. In particular promising are 16S RNA genes analysis for microbial communities or specific RT-PCR for obtaining quantitative data.