JOURNAL OF FOOD SAFETY, vol.26, no.1, pp.30-40, 2006 (SCI-Expanded)
A total of 100 retail samples of meat and meat products were examined for Bacillus cereus using mannitol egg yolk polymyxin (MYP) agar as a selective isolation medium. Only 22.4% of the samples contained detectable levels of B. cereus, with counts ranging from log(10) 0.69 to 4.80 cfu/g, but a large number of other organisms up to log(10) 9.06 cfu/g were sometimes observed on the plates and may have masked the presence of B. cereus or inhibited growth. Two samples of soudjouck contained significant levels of B. cereus, sufficient enough to create a public health hazard. Selected isolates were tested for diarrheal enterotoxin production by a reversed passive latex agglutination (RPLA) test kit. Results showed no difference in the toxin production of B. cereus between beef, ground meat, soudjouck and pastrami samples. Plasmid-profile analysis and susceptibility to the six commonly used antimicrobial agents were done on selected B. cereus isolates. About 96.4% of the isolates contained plasmids. Plasmid sizes ranged between 2.5 and 3.5 kb. The isolates showed a high rate of resistance to oxacillin (OXA) and amoxicillin (AMC) and a low frequency of resistance to the other antimicrobial agents, with all of them being susceptible to vancomycin (VAN). Approximately 54% of the isolates showed multiple resistance. There was no apparent relationship between drug resistance and carriage of plasmids.