Effect of Lemongrass (Cymbopogon citratus) Essential Oil on the Survival of Multidrug-Resistant Salmonella enterica serovar Heidelberg in Contaminated Poultry Drinking Water

Drinking water contaminated with Salmonella could serve as a source for cecal colonization of the pathogen in birds. In this study, we investigated the efficacy of a generally recognized as safe—status essential oil (lemongrass essential oil, LGEO) against multidrug-resistant Salmonella enterica serovar Heidelberg (S. Heidelberg) in poultry drinking water. Farm water with and without added droppings, litter, or feed [0.5% (w/v)] inoculated with 6.0 log₁₀ cfu/mL S. Heidelberg was treated with 0, 0.03, 0.06, 0.125, 0.25, or 0.5% (v/v) LGEO and incubated at 12.5°C or 22°C for up to 7 d. The number of viable S. Heidelberg populations was determined on d 0, 1, 3, 5, and 7. At 12.5°C, all concentrations of LGEO inactivatedS. Heidelberg to non-detectable levels in water alone and water contaminated with droppings or litter by d 7 (>6 log₁₀ cfu/mL; P < 0.05). The highest LGEO concentration tested (0.5%) resulted in >5.0 log₁₀ cfu/mL reduction of S. Heidelberg on d 7 in water contaminated with feed (P < 0.05). At 22°C, all concentrations of LGEO resulted in the reduction of S. Heidelberg to non-detectable levels in water alone by d 5 (>6 log₁₀ cfu/mL; P < 0.05). Concentrations of LGEO ≥0.125% resulted in inhibition of S. Heidelberg to non-detectable levels in water contaminated with droppings from d 5 onwards (P < 0.05). The LGEO at the highest tested concentration (0.5%) resulted in >5.0 log₁₀ cfu/mL reduction of S. Heidelberg in water contaminated with litter on d 7 (P < 0.05) but did not result in reduction of the pathogen in water contaminated with feed at 22°C. Results indicate the potential of LGEO against S. Heidelberg in water alone or water containing droppings or litter, indicating its efficacy as a natural disinfectant in poultry drinking water.