Sources, Transmission, and Control of Salmonella in Vertically Integrated Broiler Chicken Production: Farm, Hatchery, and Processing Plant.

Salmonella remains one of the most important foodborne pathogens associated with poultry products, despite substantial progress in processing hygiene and antimicrobial interventions. This review critically examines the sources, transmission routes, and control strategies for Salmonella in vertically integrated broiler production systems. Attention is given to contamination originating from breeder flocks, hatcheries, feed, water, litter, grow-out farms, transport, processing environments, and finished products. Preharvest interventions, including biosecurity, breeder and hatchery control, vaccination, litter and water management, feed hygiene, probiotics, prebiotics, organic acids, essential oils, bacteriophages, and bacteriocins, are evaluated according to mechanism, evidence strength, and commercial relevance. Postharvest interventions, including scalding, picking, evisceration control, chilling, peroxyacetic acid application, carcass rinses, post-chill treatments, and finished-product verification, are reviewed in relation to microbial reduction and process control. The review also discusses quantitative bio-mapping, surveillance design, whole-genome sequencing, predictive modeling, and quantitative microbial risk assessment as tools for identifying contamination hotspots, persistent strains, and high-risk control points. Overall, effective Salmonella control requires coordinated preharvest and postharvest strategies supported by routine verification, stronger flock-to-product traceability, and field validation of interventions under commercial conditions.