A Systematic Review and Meta-Analysis on Campylobacter Species Prevalence in Chicken in Italy

Campylobacter is responsible for campylobacteriosis, the most reported foodborne gastrointestinal infection in humans in the European Union, and broiler meat was the food primarily associated with outbreaks with stronger evidence. This study aimed to revise the literature and estimate the pooled prevalence of Campylobacter spp. in three different chicken matrices in Italy from 2003 to 2023, as well as potential subgroup moderators to the observed value. The total number of eligible studies was 48. On the basis of the meta-analysis, skin and faeces matrices exhibited a high pooled proportion of Campylobacter spp., 0.62 and 0.67, respectively, whereas meat had the lowest proportion of 0.20%, with high heterogeneity detected in the three matrices I² = 97.5%-98.8%. As for the moderator subgroup analysis, Campylobacter spp. prevalence in meat was higher in the published literature (0.38) than in the national zoonoses country reports (0.10), whereas no significant difference was observed for skin matrix (p-value = 0.6). Moreover, Campylobacter spp. prevalence in the meat matrix was two times more in samples collected at the slaughterhouse step than those collected at the retail step (pvalue < 0.05). In the case of faeces, no significant differences (p-value > 0.5) were detected comparing sampling point (farm or slaughterhouse) and sample types (cloacal or caecal content). This result highlights that Campylobacter spp. is frequently inhabits the intestines of chickens, and it is detectable with a comparable frequency on the skin following the slaughtering process. Moreover, not only Campylobacter spp. persist along the food chain but also cross-contamination occurring after the primary production steps can determine a relevant prevalence of the microorganism in meat sold at retail in Italy. The outcome of this meta-analysis could be beneficial as input for future quantitative risk assessment. SUMMARY: This systematic review summarizes the prevalence of Campylobacter spp. in different chicken matrices in Italy over the last 20 years, which may be useful for conducting quantitative microbial risk assessment (QMRA) in the future. Higher Campylobacter spp. prevalence rate was observed in faeces (67%) and skin (62%) compared to the meat matrix (20%), suggesting frequent cross-contamination events during slaughtering, processing and handling. The result showed that Campylobacter spp. are isolated from meat at retail (10%) and most of them belong to pathogenic species for the consumers.