Effect of Nigella sativa (seed and oil) on the bacteriological quality of soft white cheese

The effect of Nigella sativa seed (1% and 3%) and oil (0.3% and 1%) on some food poisoning and pathogenic bacteria as well as on the total bacterial count TBC (cfu/g) in soft white cheese prepared from raw ewe s milk and labratory pasteurized ewe s milk inoculated with Staphylococcus aureus, Brucella melitensis and Escherichia coli at a concentration of 1×106 cfu/ml were carried out. Cheese samples were examined for bacterial count at: zero, 2nd, 4th and 6th days of storage at refrigerator temp. Results showed that there was Significant decrease (P 0.05) in TBC, Staphylococcus aureus, Brucella melitensis and Escherichia coli count in cheese samples treated with N. sativa seed (1% and 3%) and oil (0.3% and 1%) with pronounced concentration dependent inhibition in contrast to control cheese samples which exerted significant increase in bacterial counts as it reached 2.8×107, 2.95×106, 2.22×106 and 2.885×106 cfu/g for TBC, Staph. aureus, Br. melitensis and E. coli respectively at the 6th day of storage at refrigerator temp. N. sativa oil (0.3% and 1%) was significantly more affective (P 0.05) as antibacterial agent than seed (1% and 3%) respectively. No significant differences (P 0.05) in the susceptibility of Staph. aureus, Br.melitensis and E. coli to the antibacterial effect of N. sativa seed (1% and 3%) and oil (0.3% and 1%) were observed in treated soft white cheese.