A total of 2100 g fresh chicken fillet were divided into 7 equal groups (3x100 g of each). 1st group is negative control ( free from Bucillus cereus ) and others six group was been inoculated by Bacillus cereus with infective dose 5.2x107cfu/g . 2nd group is positive control, 3rd and 4th groups had been treated with thyme oil (1% and 1,5%) respectively,5th and 6th groups were treated with nisin (50 ppm and1 00 ppm) respectively, and 7th group was treated with mixture of thyme and nisin at 1.5% and 100ppm respectively, . the treated and untreated chicken fillet samples had been stored at 4˚C in refrigerator. The groups were examined every 48 hours for sensory examination (overall acceptability) and Bacillus cereus count. Thyme oil (1% and 1.5%) decreased count of Bacillus cereus (cfu/g) from 4.9x108 (initial load) to 3.9 x108 and 2.3x108 with reduction percentages 20.4% and 53.1% on 4th day and 6th day of storage, respectively. nisin (50 and 100 ppm) decreased count of Bacillus cereus (cfu/g) to 6.5x107 and 3.4x107 with reduction percentages 86.7% and 93.1% on 8th day and 10th day of storage, respectively. Mixture of (thyme and nisin) decreased count of Bacillus cereus (cfu/g) to 7.5x106 . Generally, mixture of thyme oil and nisin (1,5% and 100ppm) proved to be more efficient than other concentrations in suppression of Bacillus cereus growth in fillet
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