부산대학교 도서관

Food - borne illness is a serious health threat and has significant economic consequences for people for people in both the developing and developed world and Bacillus cereus are one of the most common pathogens and a major cause of food - borne illness in humans worldwide(Gomez et al., 1997: WHO, 2002 Patrick et al., 2004).From emetic - type B. cereus food posing has been reported(Marhler et al., 1997) and severe forms of the diarrhea syndrome have also been reported, including a necrotic enteritis causing three death,(Lund et al., 2000) other Bacillus species, particularly B.subtilis, B.thuringiensis, B.mycoides, B.cereus, have been recognized as food poisoning bacteria. Recently, social well - being trends are Ready - eat or ready - to - use vegetables are subjected to minimal or no processing before consumption. (Park, Si-Hong., 2006). Raw foods of plant origin are a major source of B.cereus in food and the presence of Bacillus species in plant food is the result of soil contamination rather than a specific association between the microorganism and plants (priest, 1989). Cereal products and various type of peas and beans have been found to be frequently contaminated with B.cereus (Blackly and priest, 1980; Rosenkvist and Hansen, 1995). nucleotide sequences and specific probe of Bacillus cereus group bacteria were suggested based on gyrB gene sequence that encode the subunit B protein of DNA gyrase (topoisomerase type II) (20).In this present study, specific primers and probe were designed based on gyrB gene sequences for quantitative PCR assay to Bacillus cereus group bacteria and a real - time PCR was developed based on copy number of genomic DNAs of Bacillus cereus. Quantitative standard curve of real time PCR was obtained with quantitatively diluted genomic DNA of Bacillus cereus. Amplification plot showed quantitative detection of Bacillus cereus from 4.5×106 to 4.5×103 CFU/g of lettuce with 6 repeated experiments. Based on real time PCR result, the minimum detection limit of artificially contaminated Bacillus cereus is 4.5×103 CFU/g of lettuce. This real time PCR method could be applicable to the detection and quantification of Bacillus cereus group bacteria in vegetable samples.