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Food safety remains a pressing concern in densely populated countries like India, where contaminated food poses serious health risks, especially to vulnerable groups such as children, the elderly, pregnant women, and immunocompromised individuals. The emergence and spread of antimicrobial resistance (AMR) in food-producing animals and food products further exacerbate these risks, representing a silent but significant threat to public health.

This thesis investigates AMR across dairy and poultry value chains, as well as in traditional fermented food, in diverse Indian regions, using both phenotypic and genotypic analyses. Risk assessments were conducted to evaluate the public health risks associated with AMR in these food systems.

In the dairy chains of Assam and Haryana, methicillin-resistant and β-lactamase-producing bacteria were widely detected. The samples exhibited multidrug-resistant (MDR) strains in milk isolates, with pasteurized milk showing unexpectedly more prevalence of MDR strains, suggesting post-pasteurization contamination due to poor handling. No significant farm-level risk factors, such as herd size or farmer knowledge, could be associated with the presence of AMR.

In poultry from Karnataka and Assam, non-typhoidal Salmonella (NTS) and E. coli were highly prevalent, with Karnataka showing notably higher resistance rates. MDR was common in Salmonella enterica serovars Choleraesuis, Infantis, and Kentucky, posing serious zoonotic risks. Contamination with AMR bacteria in treated water used for feeding birds may indicate biosecurity lapses. Risk modelling confirmed that sampling matrices and regional differences influenced the likelihood of detecting resistant pathogens.

Traditional fermented food products from the North-eastern states of India revealed the presence of lactic acid bacteria (LAB) with probiotic potential in some food products. However, many samples lacked LAB and instead contained pathogenic bacteria, including multi-resistant staphylococci, highlighting hygiene-related risks. This study emphasized the potential for these food products to transmit AMR if consumed without adequate processing.

Collectively, these findings underscore the urgent need for effective pasteurization, improved hygienic handling, rational antibiotic use, and robust biosecurity in food production. The results advocate for integrated food safety strategies, systematic AMR monitoring, and studies in expanded geographical areas to inform public health policies and safeguard India’s food supply.