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 1×10 6 cfu/ml were carried out. Cheese samples were examined for bacterial count at: zero, 2 nd , 4 th and 6 th 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 2.8×10 7 , 2.95×10 6 , 2.22×10 6 and 2.885×10 6 cfu/g for TBC, Staph. aureus , Br. melitensis and E. coli respectively at the 6 th 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.