In a paper published in the journal, Epidemiology and Infection, O. Bucher of the University of Guelph in Canada and co-authors at the Public Health Agency of Canada and at Mississippi State University in the US describe a scoping study and systematic review-meta-analyses (SR-MAs), which were conducted to evaluate the effectiveness of various interventions for Salmonella in broiler chicken, from grow-out farm to secondary processing.

The resulting information was used to inform a quantitative exposure assessment (QEA), comparing various control options within the context of broiler chicken production in Ontario, Canada.

Multiple scenarios, including use of two separate on-farm interventions (CF3 competitive exclusion culture and a two-per cent lactose water additive), a package of processing interventions (a sodium hydroxide scald-water disinfectant, a chlorinated post-evisceration spray, a trisodium phosphate pre-chill spray and chlorinated immersion chilling) a package consisting of these farm and processing interventions and a hypothetical scenario (reductions in between-flock prevalence and post-transport concentration), were simulated and compared to a baseline scenario.

The package of on-farm and processing interventions was the most effective in achieving relative reductions (compared to baseline with no interventions) in the concentration and prevalence of Salmonella by the end of chilling ranging from 89.94 per cent to 99.87 per cent and 43.88 per cent to 87.78 per cent, respectively.

Contaminated carcasses entering defeathering, reductions in concentration due to scalding and post-evisceration washing, and the potential for cross-contamination during chilling had the largest influence on the model outcomes under the current assumptions.

Scoping study provided a transparent process for mapping out and selecting promising interventions, while SR-MA was useful for generating more precise and robust intervention effect estimates for QEA, concluded the researchers. Bucher and co-authors commented that realisation of the full potential of these methods was hampered by low methodological soundness and reporting of primary research in this area.

Reference

Bucher O., A. Fazil, A. Rajic, A. Farrar, R. Wills and S.A. McEwen. 2011. Evaluating interventions against Salmonella in broiler chickens: applying synthesis research in support of quantitative exposure assessment. Epidemiology and Infection, FirstView Article: 1-21. DOI: 10.1017/S0950268811001373

Further Reading

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November 2011