Microbial Contamination of Utensils and Washing Water in a Nigerian Tertiary Institution Restaurant: A Comprehensive Risk Assessment

Abstract

Background: Foodborne illnesses remain a critical public health challenge in developing nations, with contaminated food contact surfaces serving as significant reservoirs for pathogenic microorganisms. Restaurants in tertiary institutions are particularly vulnerable settings, where large, diverse populations consume daily meals under conditions that are rarely subject to rigorous microbiological surveillance. Aim: This study aimed to assess the microbiological contamination of food-contact utensils, specifically spoons and dishes, and associated washing/rinsing water in restaurants in tertiary institutions in Offa, Kwara State, Nigeria. Methods: Samples were collected from canteen restaurants at the Federal Polytechnic Offa and were analysed using standard cultural, morphological, and biochemical identification methods. Microbial loads were estimated by spread-plate and streak-plate methods on Nutrient Agar, MacConkey Agar, and Potato Dextrose Agar. Organisms were identified through Gram staining and biochemical tests including catalase, coagulase, motility, starch hydrolysis, and carbohydrate fermentation assays. Results: Total Aerobic Plate Counts (TAPC) ranged from 1.4 × 10³ to Too Numerous To Count (TNTC) CFU/mL across all sample types. Total Coliform Counts (TCC) and Total Fungal Counts (TFC) were equally elevated, with TCC for spoons reaching 7.6 × 10³ CFU/mL and TFC values up to 6.0 × 10³ SFU/mL. Bacterial isolates identified included Staphylococcus aureus, Escherichia coli, Shigella spp., Salmonella spp., Campylobacter jejuni, Enterococcus spp., Micrococcus spp., and Bacillus spp. Fungal isolates comprised Aspergillus niger, Candida albicans, Rhizopus spp., Cladosporium spp., Fusarium spp., and Epicoccum nigrum. Conclusion: The high microbial burden across all sample categories reflects systemic failures in sanitation protocols, utensil washing practices, and hygiene education among food handlers. Urgent institutional and regulatory intervention is required to mitigate the risk of foodborne illness outbreaks within these educational settings.