Comparative Analysis of Microbial Load and Public Health Implications of Factory-Processed and Locally Prepared Foods in Port Harcourt, Nigeria

Abstract

Foodborne microbial contamination remains a major public health challenge in low- and middle-income countries, where both factory-processed and locally prepared foods contribute significantly to daily dietary intake. This study evaluated the microbial population, diversity, and public health risks associated with selected factory-processed and locally prepared foods sold in Port Harcourt, Nigeria. A total of forty (40) food samples comprising Hollandia yoghurt drink (n = 10), Gino curry powder (n = 10), industrial yeast (n = 10), and home-prepared Hibiscus sabdariffa beverage (zobo) (n = 10) were analysed using standard microbiological methods. Total heterotrophic bacterial (THB) and total heterotrophic fungal (THF) counts were determined using nutrient agar and Sabouraud dextrose agar, respectively. Representative isolates were identified using cultural, morphological, biochemical, and microscopic methods. Total heterotrophic bacterial counts ranged from 1.0 × 10⁴ to 3.1 × 10⁴ CFU/g or mL. Gino curry powder recorded the highest bacterial load (3.1 × 10⁴ CFU/g), while yoghurt drink recorded the lowest (1.0 × 10⁴ CFU/mL). Total fungal counts ranged from 1.0 × 10² to 5.3 × 10² CFU/g or mL, with industrial yeast showing the highest fungal burden. Seven bacterial genera were identified: Lactobacillus, Bacillus, Staphylococcus, Micrococcus, Pediococcus, Enterococcus, and Proteus. Fungal isolates included Mucor, Rhizopus, Fusarium, Penicillium, and Saccharomyces cerevisiae. The predominance of Staphylococcus species suggests post-processing contamination through handling. The detection of Fusarium and Penicillium species raises concerns regarding potential mycotoxin production. Although microbial counts were within moderate ranges, the presence of opportunistic pathogens highlights potential public health risks, particularly under improper storage conditions. This study underscores the need for improved hygiene practices, routine microbiological surveillance, and regulatory oversight to safeguard consumer health.