Essential oils for pre-harvest control of Salmonella in poultry: mechanisms, efficacy, and integrated applications

Salmonella remains a major foodborne pathogen associated with poultry production worldwide, with increasing concern over antimicrobial resistance driving interest in alternative control strategies. Essential oils (EOs), complex mixtures of plant-derived volatile compounds such as thymol, carvacrol, cinnamaldehyde, and eugenol, have gained attention due to their antimicrobial, anti-virulence, and immunomodulatory properties. This narrative review synthesizes current evidence on the use of EOs for pre-harvest control of Salmonella in poultry systems. Mechanistic studies demonstrate that essential oils disrupt bacterial membranes, inhibit biofilm formation, and suppress motility and virulence factors, with additional synergistic interactions reported with organic acids (OAs) and conventional antimicrobials. In vitro studies consistently show strong inhibitory activity against poultry-associated Salmonella enterica serovars. In vivo studies in broilers, layers, and breeders indicate that dietary supplementation can reduce intestinal colonization and fecal shedding while improving gut morphology, microbiota balance, immune responses, and growth performance. Applications in drinking water systems, feed decontamination, and combination strategies further support their role in integrated control programs. However, practical implementation is influenced by compositional variability, processing stability, sensory limitations, regulatory considerations, and economic feasibility. Advances in formulation technologies and field validation will be essential to improve consistency and support the integration of EOs into multi-hurdle Salmonella control strategies in poultry production.