Prevalence and Antimicrobial Susceptibility Patterns of Salmonella enterica Serovars Along the Dairy Value Chain: A One Health-Relevant Surveillance of Dairy Farms.

Abstract

Raw milk is highly prone to microbial contamination and can carry Salmonella enterica serovars-like zoonotic pathogens. This study follows the One Health-informed framework to investigate the occurrence and potential contamination pathways of Salmonella enterica serovars along the raw milk value chain in Bareilly, Uttar Pradesh, Northern India. A total of 900 samples consisted of raw milk (150), milk bucket swabs (150), milkers' hand swabs (150), and farm floor swabs (150) collected from one local dairy farm, and one institutional dairy farm, and one retail milk outlet over a 6-months period. Overall, 19 samples (2%) were Salmonella enterica serovars positive, where pathogen occurrence was noted as 4.7% in farm floor swabs, 4.7% in milking bucket swabs, and 2% in raw milk. Salmonella enterica serovars was not detected in udder swabs, towel swabs, and milker hand swabs. Antimicrobial susceptibility analysis demonstrated high Salmonella enterica serovars (n = 19) resistance to ampicillin (73.7%) and tetracycline (68.4%), whereas multiple isolates (48%) exhibited multidrug resistance as well. These findings necessitate upgraded dairy hygiene practices, controlled antimicrobial use in veterinary medicine, and integrated One Health-relevant surveillance to mitigate raw milk consumption-associated public health risks in the studied region.