Molecular Identification, Physicochemical Analysis, and Antimicrobial Resistance Profiles of Bacteria Isolated from Cooked Rice Hawked in Bodinga Markets

Abstract

Street food vending is an indispensable aspect of food systems in Nigeria, providing affordable meals to low-income populations and employment opportunities for millions of people. Cooked rice is among the most commonly hawked foods due to its affordability, convenience, and cultural relevance. However, the safety of street vended rice is of major public health concern because its physicochemical properties—high moisture content, near neutral pH, and carbohydrate rich matrix—make it a suitable environment for bacterial growth if handled or stored improperly. This study investigated the microbial quality, physicochemical characteristics, and antimicrobial resistance (AMR) profiles of bacteria to be isolated from cooked rice vended in Bodinga markets, Sokoto State, Nigeria. A total of 120 rice samples will be collected from 40 vendors across six major markets between January and June 2023. Microbiological analysis included total viable counts and selective culturing, followed by 16S rRNA gene sequencing for molecular identification. Physicochemical parameters to be measured included pH, moisture content, water activity, and soluble solids. Antimicrobial susceptibility will be determined using the Kirby-Bauer disk diffusion method in accordance with CLSI (2022) guidelines. The results revealed that microbial counts ranged from 4.2 to 7.1 log CFU/g, exceeding ICMSF limits for ready-to-eat foods. Predominant bacterial isolates may included in percentage s Bacillus cereus (%), Staphylococcus aureus (%), Escherichia coli (%), and Salmonella spp. (%). Physicochemical analysis indicated a mean moisture content of expected amount of 65 ± 3.2% and a pH of 6.5 ± 0.4, conditions favorable for microbial survival and proliferation. Alarmingly, presence of about 40% of isolates will exhibit multidrug resistance (MDR), and will have a high resistance rates against ampicillin (%), tetracycline (70%), and ciprofloxacin (%). A significant correlation was observed between moisture content and microbial load (r = 0.72, p < 0.001). The findings may limited the urgent need for food safety interventions, including hygiene training for vendors, implementation of microbiological monitoring programs, and integration of AMR surveillance into Nigeria’s food safety framework.