Phenotypic and Genotypic Approaches to Enhance Disinfection Strategies for On-Farm Control of Salmonella

Salmonella is a globally significant food-borne pathogen capable of persisting on-farm, posing a significant risk to the food chain through contamination of subsequent production stages. On-farm persistence varies between Salmonella serovars, but the underlying reasons for this remain poorly understood. This thesis aimed to investigate differences in susceptibility between Salmonella serovars and isolates to commercially available disinfectants, to identify genetic factors conferring reduced susceptibility, and to assess the potential of efflux pump inhibitors (EPIs) to enhance disinfectant efficacy. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays were used to screen nine serovars. Salmonella 13,23:i:- isolates (n=20) demonstrated significantly reduced susceptibility to two aldehyde and two Quaternary Ammonium Compound (QAC) products (p