Preharvest strategies for reducing Salmonella prevalence in broilers: Effects of organic acids and litter treatments

Abstract

Salmonella is a major foodborne pathogen closely monitored to ensure the safety of poultry-derived food products. Although illnesses are often attributed to improper handling or cooking, contamination frequently originates during live production. Therefore, the implementation of effective preharvest interventions intended to reduce Salmonella prevalence in the birds and the environment are essential to minimize the risk of contamination in final poultry products. This study evaluated two preharvest strategies, including organic acids supplementation via drinking water and litter treatments to control Salmonella prevalence in broilers. In experiment 1, the objective was to introduce Salmonella into a broiler flock and evaluate whether continuous supplementation of organic acids in drinking water influenced bird performance or Salmonella prevalence during processing. A total of 1,872 day-old male broilers (YPM × Ross 708) were randomly allocated to 72 floor pens (26 birds/pen) and provided either untreated water (water control), a blend of lactic, acetic, and propionic acids (OAB), or citric acid (CA). All birds were orally inoculated on day 7 with nalidixic acid-resistant Salmonella Enteritidis. Samples collected included chick papers, litter, ceca, and carcass rinses, and Salmonella detection was performed using the Molecular Detection System (MDS) method. Enumeration using XLT4+ agar was not possible because bacterial levels were below the detectable threshold. Salmonella was detected in chick papers and litter at placement but declined to undetectable levels by the end of the study, requiring enrichment for confirmation. Organic acid supplementation via drinking water did not influence Salmonella prevalence in ceca, carcass rinses, or litter (P > 0.05). However, CA reduced body weight (BW) on day 39 (P = 0.034). Using the same litter from the Experiment 1, experiment 2 evaluated two consecutive grow-outs to determine the effects of three litter treatments: untreated litter (litter control), windrow composting (WC), or aluminum sulfate (AS), combined with 3 continuous organic acid supplementation in drinking water. Samples collected included litter swabs, chick papers, ceca, and carcass rinses. Neither litter nor water treatments alone reduced Salmonella prevalence in litter or birds. In the litter control and WC groups, supplementation with OAB and CA increased carcass Salmonella prevalence compared to the water control, whereas no differences among water treatments were observed in AS-treated litter. Both litter and water treatments influenced bird performance. Broilers raised on WC-treated litter exhibited greater BW during the early stages of growth. A significant interaction between litter and water treatments was observed for FCR during the first grow-out, birds supplemented with CA had the lowest FCR when combined with AS-treated litter. Across both grow-outs, CA and OAB increased water to feed intake ratio (P < 0.05). Overall, both litter treatment and organic acid supplementation contributed to improvements in broiler performance, but neither approach completely eliminated Salmonella from birds nor litter under the conditions evaluated. These findings highlight the persistence of Salmonella in broiler production, indicating that while reductions can occur over time, complete elimination remains difficult to achieve with the interventions evaluated.