Effect of irradiation with black cumin (Nigella sativa) on the biochemical properties and microbial population of beef at different days of interval at ambient temperature

Abstract

This study explored how combining gamma irradiation with black cumin (Nigella sativa) extract affects the biochemical makeup and microbial levels of beef stored at ambient temperature over time. Fresh, boneless beef samples were first treated with a 2% solution of black cumin extract, then exposed to gamma radiation at doses of 0 (as a control), 3, 5, and 7 kGy using a cobalt-60 (⁶⁰Co) irradiator. Biochemical analyses such as peroxide value (POV), free fatty acids (FFA), and thiobarbituric acid reactive substances (TBARS) were performed on treated samples at 0, 3, 5, and 7 days. Microbial analyses included total coliform count (TCC), total viable count (TVC), total yeast and mould count (TYMC), and the existence of Salmonella spp. and Staphylococcus spp. Results demonstrated significant (p<0.01) increases in POV, FFA, and TBARS values with both greater radiation exposure and prolonged storage which enhanced lipid oxidation. Microbial counts were equally affected by both treatment and time, with large increases in TCC, TVC, and TYMC, whereas Staphylococcus spp. exhibited a general decline and Salmonella spp. varied depending on the treatment. The factorial experimental design indicated considerable interactions (p<0.01) between radiation dose and storage term on most biochemical and microbiological markers. These observations show that irradiation in association with black cumin (Nigella sativa) extract can influence both oxidative stability and microbiological safety of beef and that optimization of dose and storage conditions are important to ensure product quality under ambient temperature.