Scomber japonicus

Fish rolls in Nigeria are nutritionally imbalanced, and the impact of varying fish concentrations on their microbial safety and shelf life is not well understood. This study was carried out to assess the nutritional composition and microbial quality of fish rolls made with Scomberjaponicus concentrate. Five formulations were prepared with S. japonicus fish concentrate (0%,10%, 20%, 30%, 40%), Standard analytical methods (AOAC, 2020) were used to determine the proximate composition, while microbial analysis was performed using standard microbial techniques to determine microbial and fungal contamination levels. There was significant (P<0.05) increases in protein, fat, ash, and moisture contents with higher levels of inclusion. Protein content increased from 9.77% to 25.54%, while carbohydrate content decreased correspondingly from 58.64% to 25.48%. Bacterial counts ranged from 3.7 × 10² to 1.0 × 10³ cfu/g, and fungal counts from 0.2 × 10² to 1.7 × 10² cfu/g, all below the recommended limits of 5 × 10⁵ cfu/g set by the FAO. (ICMS, 2002). The major bacterial isolates included Bacillus sp., Staphylococcus sp., Pseudomonas sp., and Enterobacter sp., while Aspergillus sp., Saccharomyces sp., and Penicillium sp. were the predominant fungi. The study suggest that fish rolls made with S. japonicus significantly enhances their nutritional value, without exceeding acceptable microbial limits. An optimal fortification level of 20% fish concentrate was recommended to balance nutritional quality, sensory acceptability, affordability and microbial safety.