Prevalence and Antimicrobial Resistance Pattern of Listeria Monocytogenes in Ready t o Eat Foods in Tamil Nadu, India

Abstract

Objectives: To examine the prevalence and antibiotic resistance pattern of Listeria monocytogenes in RTE food to understand the risk of contamination in the food industries. Methods: A total of 105 different samples of RTE foods, including curd, cheese, almond milk, banana milkshakes, chocolate, and strawberry milkshakes were collected from street vendors and departmental stores in and around Kanchipuram, Tamil Nadu. As per ISO 11290-1:2017(E) protocol suspected Listeria colonies were selected and identified using standard biochemical tests. Positive colonies were then confirmed by PCR, and isolated confirmed strains were tested for their susceptibility to 12 widelyused antibiotics. Findings: Of the 105 samples, 15 (14.28%) showed a positive, and the overall extent of Listeria monocytogenes in RTE foods was about 14.3%. The results indicate that curd (n=10) and cheese (n=10) had the highest prevalence of L. monocytogenes (30%), followed by almond milk (25%), banana milkshake (13.33%), chocolate, and strawberry, which had a 10% prevalence each. Moreover, antibacterial susceptibility to 12 antimicrobial agents of 25 isolates of L. monocytogenes screened from fifteen RTE foods were tested and highlighted the emergence of multi-drug resistant patterns. Novelty: Our findings reveal that the Kanchipuram district has a high incidence of L. monocytogenes in RTE foods, particularly cheese, curd, and almond milk, which may cause multidrug resistance to the antibiotics used to treat listeriosis. Keywords: Foodborne Pathogen; Listeria monocytogenes; Ready to eat Food; Antimicrobial Resistance