An evaluation of survival and detection of Campylobacter jejuni and C. coli in broiler caecal contents using culture-based methods

Authors


J.D. Rodgers, Department of Food and Environmental Safety, Veterinary Laboratories Agency (Weybridge), New Haw, Addlestone, Surrey KT15 3NB, UK. E-mail: j.rodgers@vla.defra.gsi.gov.uk

Abstract

Aims:  To evaluate the culture specifications of the 2008 EU baseline survey for Campylobacter spp. in broiler flocks at slaughter, by assessing the detection of thermophilic Campylobacter in chicken caecal contents by culture on selective agar with or without enrichment culture. Additionally, to assess the impact of sample storage time on Campylobacter detection.

Methods and Results:  Serial dilutions of pooled caeca samples in phosphate-buffered saline or Campylobacter-negative caecal contents were cultured micro-aerobically at 41·5°C on mCCDA, Karmali and Preston agars before and after enrichment in Exeter broth. Direct culture on mCCDA showed a higher isolation rate than for Karmali or Preston agars, but a similar isolation rate to enrichment. Enumeration of samples showed the numbers of viable bacteria dropped slightly during storage.

Conclusions:  Direct culture on mCCDA was the most sensitive method for detection of Campylobacter, and samples with 104 CFU g−1 were still detectable after 6 days.

Significance and Impact of the Study:  Comparison of prevalence results from the 2008 EU baseline survey will need careful interpretation as the different media specified vary in their sensitivity to detect thermophilic Campylobacter. Delayed culture for up to 80 h after collection should have little impact on detection rate.

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