A total of 160 quarter milk samples from 40 dairy cows were obtained from Assiut dairy farms under sterile conditions to study
of Bacillus cereus with bovine mastitis. Collected the association milk samples were tested with California Mastitis test (CMT).
(9.38%) of the tested
15 Bacillus cereus was recovered from quarters of which 60% were CMT positive. 30% of the dairy
Cows udder's were positive for B. cereus, whereas the organism was detected in the faeces of 35% of the examined dairy cows. 6 of 40 cows (15%) harboured B. cereus in their udders and gastrointestinal tracts. B. cereus organisms isolated from milk (15 strains) and faeces (14 strains) were tested for their antibiotic sensitivity and there was variance of resistance. Most of the isolated B. cereus strains from milk were sensitive to tetracycline (93.3%) and streptomycin (73.3%). Recovered strains from faeces were sensitive to gentamicin (85.7%), tetracycline (85.7%) and streptomycin (78.6%), but all the strains were resistant to ampicil lin. The significance of B. cereus as a cause of mastitis and foodborne illness was discussed.