Nitrite free fresh sausage formulated with innovative nitrite alternatives and their impacts on shelf life and quality attributes during refrigerated storage

Nitrite is a vital preservative widely used in meat processing. Carcinogenic N-nitroso compounds discovered in processed meat products became serious impacts negatively affect meat industry. The present study provided a nitrite free fresh sausage with a novel method to substitute nitrite with a mixture consisted of (400 ppm nisin+25 ppm Zinc oxide nanoparticles+ 1% Hibiscus sabdariffa extract +1% chitosan) employing nisin (N) and Zinc oxide nanoparticles (ZON) as antimicrobials, chitosan (C) as antioxidant and H. sabdariffa extract (H) for color improving. In vitro antibacterial activity of nisin and ZON against Clostridium perfringens reference strain was estimated using agar well diffusion test. H. sabdariffa extract was evaluated for its phenolic and flavonoid contents as well as its phytochemical profile was analyzed using HPLC. Four variants of fresh sausage with different treatments were prepared: Nitrite (NT) treated, (N.C.H), (ZON.C.H) and (N.ZON.C.H), packed in polyethylene bags and kept in a refrigerator at 4 ?C. Samples were examined to assess their pH, microbiological evaluation (aerobic plate, Enterobacteriaceae, yeast and mold counts), also, sensory assessment and shelf life were evaluated. Results exhibited that nisin and ZON have potent antibacterial activity against Cl. perfringens with inhibition zone of 30 mm and 15 mm compared to 30 mm of sodium nitrite. Hibiscus extract manifested a high phenolic content about 27.213 mg Gallic acid /g, 2.896 mg QE/g for flavonoids and about 19 main phenolic compounds were detected by HPLC. Results exhibited that N.ZON.C.H group samples showed the lowest pH values, APC, Enterobacteriaceae, yeast and mold counts among sausage variants. Regarding shelf life and sensory evaluation, as expected, N.ZON.C.H showed the highest sensory scores and shelf life (18 days) followed by N.C.H and ZON.C.H that remained accepted till 15th and finally NT till 12th day of cold storage. Results suggested that combination of nisin, ZON, chitosan and H. sabdariffa extract would be a promising new strategy to replace sodium nitrite and improve safety and quality of fresh sausage.