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104 CFU/mL or g) was found in 7% of milk and fast food samples. Three B. cereus group species (B. cereus, B. thuringiensis and B. pseudomycoides or B. mycoides) were identified. After time intervals of mild heat pre-exposure at 42 °C or exposure to other stresses, B. cereus developed an increased thermotolerance at 50 °C/20 min. This thermotolerance was pronounced after exposure of B. cereus cells to 42°C /1 h and 2.5 % salt / 30°C/ 40 min with a 3.9 CFU log increase compared to those exposed to lethal treatment only. Molecularly, RT-qPCR results revealed up-regulation of dnaJ gene expression in pretreated cells compared to the lethal treated cells only. Overall, these results confirmed the heat resistance occurs in B. cereus during food processing, which results in its survival in the food products.]]>
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104 colony forming units (CFU)/ g) was found in 2% of positive samples, with a higher percent in meat sausage (33.33%). Whereas 15.5% of positive samples harbored B. cereus with counts ranging from >1x103-104 CFU/g. Molecular analysis of B. cereus enterotoxin genes using multiplex polymerase chain reaction (PCR) revealed that both ces and nhe genes were detected in 100% of the examined isolates, while cytk and hbl genes were present only in 9.52% and 23.8% of analyzed isolates, respectively. These findings, involving a higher occurrence of B. cereus and their toxin genes in meat and chicken products represent a serious public health concern in Egypt.]]>
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