Interventions Effects on Campylobacter Populations in Poultry and Poultry Meat

<p>Poultry is a major source of Campylobacter infection through undercooked meat and cross-contamination of other foods in the kitchen. By assessing strain diversity and constructing epidemiological models to estimate their impacts on possible interventions, this project seeks to assess whether practical interventions can be implemented to reduce the levels of Campylobacter before meats reach the kitchen.</p>

This project will sample all stages of broiler chicken production from farm to retail in order to determine the incidence, level and type of Campylobacter colonisation of chicken, and carcass contamination, in commercial poultry production. Strain diversity will be addressed using a combination of molecular and traditional culture methods on chickens:
<ul><li>on farm</li>
<li>pre- and post-thinning</li>
<li>upon transport</li>
<li>at slaughter</li>
<li>during processing</li>
<li>on the final carcass</li></ul>

<p>This will provide data that will be used to construct epidemiological models to estimate the impact of implementing multiple interventions on Campylobacter population levels and diversity.</p>

The five operational objectives are:
<ol><li>establish methods to reliably enumerate and capture strain diversity of campylobacters in commercial poultry production, both on farm and during processing. This will be achieved by the enumeration and discrimination of strain diversity with enumeration performed using modified Cefoperazone Charcol Desoxycholate Agar and discrimination by DNA colony hybridization.</li>
<li>establish a baseline for the survival and transfer of Campylobacter types on carcasses from colonised flocks. To achieve this:</li>
<ul><li>Firstly the baseline prevalence and diversity in broiler chicken flocks will be determined. Flocks will be monitored by examining how means and variances vary over time, including the impact of different seasons, and the distribution of strain diversity across the samples.</li>
<li>Secondly the degree of process contamination from Campylobacter positive flocks will be estimated. Campylobacter populations will be estimated from the caecal contents of chickens. Similarly viable Campylobacter populations will be estimated from carcass samples from positive flocks post slaughter and samples collected from the chicken processing plant. The efficacy of the disinfectant used throughout the cleaning regimes will also be tested.</li>
<li>Thirdly the survival and transfer of campylobacters on carcasses will be investigated. Neck skin samples will be taken from selected processing stages as these have been shown to harbour campylobacters.</li></ul>

<li>assess the efficacy of on-farm biosecurity interventions in terms of Campylobacter prevalence, colonisation and strain diversity. A comparison of on-farm interventions will be made. The proposed interventions have to be permissible and commercially feasible and will be measured against current production standards in terms of productivity and flock health.</li>
<li>assess how process changes affect contamination of chicken meat by campylobacters. A comparison will be made of post-harvest interventions.</li>
<li>use mathematical models to assess the causes and consequences of Campylobacter strain diversity and turnover, both on farm and during processing. A multi-strain model will be developed with rapid clearance and re-infection, which will capture both the dynamics of dominant strains and the statistical distribution of multiple low prevalence subtypes. Statistical data analysis of strain diversity, strain turnover, and intervention efficacy will be made as part of the empirical work packages.</li></ol>

<p>The outputs will be used to assess the effectiveness of various interventions in reducing human exposure to Campylobacter. </p>