Systematic review and meta-analysis of the impact of decontamination interventions on the prevalence and concentration of Salmonella in broiler chickens during primary processing

Systematic review and meta-analysis aggregate quantitative data from different studies into unified effect size estimates with better statistical power in risk assessment model parameterisation. This study uses systematic review and meta-analysis to estimate Salmonella decontamination during broiler slaughter from scalding to post-chilling, with meta-regression applied to explore modifier variables. Data from 161 studies published between 1998 and 2022 was extracted from thirty-five articles identified in the systematic review process with meta-analysis and meta-regression performed using the metafor package (version 2.0-0) in R statistical environment (version 3.6.0). The analysis revealed carcass wash (1.31 log₁₀ CFU/carcass reduction in odds; P < 0.01) and chilling (121.50% reduction in relative risk; P < 0.01) had significant reduction on Salmonella concentration and prevalence, respectively. Chemical additives reduced the concentration (0.98 log₁₀ CFU/carcass; P < 0.01) and prevalence (64.74% relative risk; P < 0.01) but the efficacy of physical methods was not conclusive. Application of decontaminants through immersion was superior (0.90 log10 CFU/carcass; P < 0.01) to spraying (0.72 log₁₀ CFU/carcass; P < 0.01). Adjusting the pH sequentially of electrolysed water, acetic acid and trisodium phosphate reduced the odds of Salmonella concentration by more than 2 log cycles and the relative risk by more than 100%. The results provide trends in the concentration and prevalence of Salmonella during the broilers slaughter process with application of decontamination interventions and provide a basis for control decision-making and quantitative microbial risk assessment.