Protective efficacy of nanoencapsulation of algal extract for preventing and controlling Clostridium botulinum in fish products

Research is being conducted on the usage of algae extracts as natural preservatives in the storage of fish products to extend shelf life, maintain quality and safety, and satisfy consumer preferences. Laurencia obtusa (Hudson), Actinotrichia fragilis (Forsskål) Børgesen, and Gracilaria dendroids sp. nov. are three species of red algae assumed to possess antibacterial properties. The objective of our study was to ascertain whether the nanocapsules of these algal extracts may be employed as a food preservation agent to inhibit the pathogenic bacteria Clostridium botulinum, which is prevalent in several fish products (fish burgers, fish fillets, Fesikh, Renga, canned tuna, canned mackerel, and canned sardines). Nanocapsules were synthesized using polymer coating techniques and characterized by zeta potential, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FT-IR) techniques. The results revealed that Fesikh showed the highest percentage (36 %) of positive isolates of C. botulinum. The antibacterial activity assessment revealed that the nanoencapsulation of A. fragilis extract exhibited the most significant antibacterial activity towards C. botulinum. This was attributed to the high concentrations of tannins, flavonoids, and phenolic compounds, which demonstrated antimicrobial properties. The findings indicated that the application of A. fragilis nanoencapsulated algae extract in the preservation of fish products decreased the total bacterial count. Meanwhile, A. fragilis was verified as a secure preservative through safety assessments, encompassing cytotoxicity, shelf life, and sensory evaluation. In summary, the algal extracts from L. obtusa, A. fragilis, and G. dendroids exhibited high levels of phenolic compounds, potent antioxidant effects, and significant antibacterial activity; hence, they can be developed as natural preservatives for fish products.