Properties of Cold Pressed Egyptian and Ethiopian Black Seed Oils and Their Impact on Microbiological Quality of Commercially Sold Kariesh Cheese

Abstract

Cheese is a common dairy product that can become contaminated by microorganisms, compromising its safety, shelf life, and flavor. Because of their antibacterial qualities, natural preservatives like fixed oils present a possible substitute for synthetic ones. The effects of Egyptian and Ethiopian black cumin (Nigella sativa L.) oils on the shelf life and sensory qualities of cheese were examined, as well as its antibacterial activity against common cheese contaminants in relative to the GC-MS chemical profiling. Five fatty acids were identified as saponified components, including palmitic acid (11.94 and 12.06%), oleic acid (22.37 and 21.88%), and linoleic acid (59.84 and 60.13%), as the primary constituents, respectively. While 1,3-bis[(trimethylsilyl)oxy]-propyl stearate (10.19 and 7.20%), 7,3',4'-trimethoxy-quercetin (8.07 and 5.40%), β-sitosterol (30.49 and 25.73%), and stigmasterol (19.71 and 25.62%), were assigned as major un-saponified compounds. The results of evaluating the microbiological quality of commercially sold Kariesh cheese after addition of 0.2% of Egyptian and Ethiopian BCO shows that they were efficient to decrease the total bacterial, Coliforms, E. coli, yeast and mold counts contamination in the treated samples. The Ethiopian BCO showed slightly higher antimicrobial effect than Egyptian BCO. This study highlights that BCO is a promising natural preservative for improving the microbiological quality and extending the shelf life of commercially sold cheese.