Abstract Description

Vegetables are an indispensable component of a healthy diet, owing to their exceptional nutritional profile, which plays a crucial role in mitigating the risk of various chronic diseases. However, they can also serve as a conduit for the transmission of foodborne pathogens, particularly when consumed in their raw or slightly cooked state. Listeria monocytogenes, are ubiquitous and virulent pathogens which pose a significant threat to human health. Thus, this study sought to evaluate the presence of L. monocytogenes in vegetables collected from retailers within the Raymond Mhlaba Local Municipality, Eastern Cape, South Africa. Vegetable samples were purchased from retail outlets in the Raymond Mhlaba local municipality and transported to the SAMRC Microbial Water Quality Monitoring Centre for analysis. Standard culture-based methods were used to isolate and enumerate presumptive Listeria monocytogenes and fecal coliforms from vegetable samples. Conventional PCR was used to molecularly confirm the identities of the presumptive L. monocytogenes. Subsequently, the confirmed L. monocytogenes were subjected to antimicrobial resistance fingerprinting to determine their antibiotic resistance profiles. A sum of 18 samples (45%) exhibited quantifiable total viable counts, all surpassing the threshold of 10^5 CFU/ml established by the Food and Agriculture Organization (2000) guidelines. Additionally, 11 samples (27.5%) demonstrated measurable total coliform levels, with the highest counts identified in carrot samples. Furthermore, fecal coliforms were detected in 13 samples (32.5%), indicating a concerning level of microbial contamination. Out of 64 presumptive Listeria isolates, only 11 (17%) were confirmed as Listeria monocytogenes through PCR. Furthermore, confirmed isolates were tested against a panel of 10 antibiotics commonly used to treat Listeria infections. The antibiotic panel yielded 100% resistance rates for Ampicillin, Penicillin, Erythromycin, and Meropenem, while Ciproflaxin and Amikacin emerged as the only two agents with 100% susceptibility. The presence of Listeria monocytogenes in vegetable samples from different retail outlets in the Raymond Mhlaba local municipality suggests that contamination may be widespread. Listeria isolates exhibited resistance to several commonly used antibiotics, a major public health concern. To address this issue, regular monitoring of vegetable samples is necessary, and improved food handling and storage practices are crucial. Moreover, antibiotic stewardship is urgently needed to prevent the emergence of antibiotic-resistant Listeria monocytogenes strains. Initiatives for public awareness ought to be established to inform consumers regarding the hazards associated with L. monocytogenes emphasizing the criticality of appropriate food handling and storage methodologies.