Detection and characterization of Listeria monocytogenes from locally processed fermented foods in Ethiope West, Delta State, Nigeria

Abstract

Outbreaks linked with foodborne pathogens and associated diseases occur regularly and pose substantial health problems to consumer safety globally. Listeriosis is a leading foodborne disease initiated by the consumption of foods contaminated by Listeria monocytogenes (L. monocytogenes ) This study evaluated the presence of . L. monocytogenes in various food samples. Locally fermented food samples (n = 80), which included Garri (n = 30), Kunu (n = 25), and Zobo (n = 25), were obtained from five open local markets in Ethiope West, Delta State, Nigeria. Food samples were screened for L. monocytogenes  using standard cultural techniques, biochemical tests including the Analytic Profile Index (API) Listeria  kit. The isolates were screened for antimicrobial resistance using the disc diffusion method, and breakpoints were interpreted based on the guidelines of the Clinical Laboratory Standard Institute. Gelatinase and lipase activities, including β-haemolysis, were determined using standard methods. L. monocytogenes was identified in 3 (3.8%) and 4 (5%) samples from Zobo and Kunu, respectively. The Garri samples were negative for L. monocytogenes, and only 7 of the 80 (8.8%) samples were positive for L. monocytogenes.  One positive sample each was obtained in the Oghara and Ogharefe markets, two from the Ugbenu market, and three from the Mosogar market. No sample was positive L. monocytogenes. for in the Oghareki market. All the isolates were penicillin-resistant but susceptible to levofloxacin and tetracycline, whereas five were resistant to clindamycin. All isolates were resistant to at least two classes of antibiotics, and the multiple antibiotic resistance (MAR) index was ≥ 0.22. Gelatinase activity was observed in one isolate, β-haemolytic activity in four isolates, and lipase activity in five isolates. This study revealed the importance of proper hygiene practices in food production and continuous surveillance of antibiotic resistance and virulence determinants in food. There is a need to adhere to standard hygiene measures in food processing environments.