Salmonella spp. in Serbian poultry production (2020–2025): Retrospective trends and farmers’ perceptions of biosecurity

Background: Salmonella enterica subsp. enterica remains a major zoonotic threat worldwide, with poultry products being a major source of human foodborne infections. Methods: A retrospective analysis of Salmonella spp. occurrence in Serbian poultry production was conducted using routine diagnostic data collected between 2020 and 2025. A total of 2453 samples from poultry farms, 147 from hatcheries and 3237 from broiler slaughterhouses were analysed. To complement the epidemiological investigation, a questionnaire was administered to 29 poultry farmers to assess difficulty associated with implementing measures from different biosecurity categories (BCs) and awareness of the economic consequences associated with Salmonella detection. Results: Salmonella spp. was detected in 2.9% of farm samples and 8.4% of slaughterhouse samples, whereas all hatchery samples tested negative. Across poultry categories, broilers showed the highest positivity rate (57/977, 5.8%), followed by layers (10/588, 1.7%) and breeders (4/741, 0.5%). Serotyping was available for a subset of farm isolates, with S. Enteritidis representing the most frequent serovar (83.3%). Generalised linear mixed-effects models identified seasonality as a significant predictor of Salmonella occurrence. 'Depopulation process', 'manure and carcass removal', 'biological vector control' and 'disease management' were perceived as most challenging BCs. Conclusion: This study provides the first integrated assessment of Salmonella occurrence across multiple components of the Serbian poultry production chain, combining retrospective surveillance data with a farmer-based evaluation of biosecurity implementation. The findings identify critical points for Salmonella transmission and provide evidence to support targeted, context-specific biosecurity interventions.