Nutritional Quality and Food Safety of Indigenous Foods: An Integrated Assessment of Dry Fish and Fermented Oil Bean Seed (Ukpaka)

Abstract

Indigenous foods are widely consumed because of their nutritional importance, availability and affordability. However, some factors, including inadequate processing, handling, and storage, may compromise their nutritional quality and safety. Therefore, this study assessed the nutritional quality and food safety of dry fish and fermented oil bean seed (Ukpaka) obtained from Eke Agbani Market, Enugu State, Nigeria. The dry fish and fermented oil bean seed collected from different vendors were respectively inoculated into Nutrient Agar (NA), MacConkey Agar, Salmonella-Shigella Agar (SSA), de Man Rogosa Sharpe (MRS) agar and Sabouraud Dextrose Agar (SDA). The inoculated plates were incubated at 37°C for 24–48 h, except for SDA plates which were incubated at 28°C for 7 days. The isolates were identified using phenotypic characterization (colony appearance, Gram reaction, and biochemical properties) and molecular characterization (PCR, 16S rRNA gene sequencing and ITS sequencing). Aflatoxin analysis, and proximate composition assessment were carried out on the indigenous foods. The total viable bacterial counts were 3.2 × 10⁴ CFU/g for dry fish and 7.8 × 10⁵ CFU/g for fermented oil bean seed, while coliform counts for bot foods were 1.4 × 10³ and 3.5 × 10⁴ CFU/g, respectively. Lactic acid bacteria count in fermented oil bean seed recorded as 6.4 × 10⁵ CFU/g while none was detected in dry fish. The isolates were Staphylococcus aureus and Escherichia coli (from dry fish), Lactobacillus plantarum, (from fermented oil bean seed) and Aspergillus niger (from both food samples). Aflatoxin analysis revealed the presence of aflatoxins B₁, B₂, G₁, and G₂ in both indigenous foods with aflatoxin B₁ recording the highest concentrations of  0.178214 µg/kg and 0.52841 µg/kg in dry fish and fermented oil bean seed samples respectively. The fermented oil bean seed had a moisture content of 59.283%, protein (26.950%), fat (3.029%), crude fibre (3.117%), ash (2.089%), and carbohydrate (5.532%). The dry fish had a moisture content (11.25%), protein (58.4%), fat (0.83%), crude fibre (0.9%), ash (11.15%), and carbohydrate (18.15%).The findings demonstrate that dry fish and fermented oil bean seed are nutritional importance but may also harbor several microorganisms which may be beneficial or pathogenic and also aflatoxins. Therefore, improved hygienic handling, processing, and storage practices are essential to preserve the nutritional quality of these indigenous foods and to ensure consumers’ safety.