Investigation on the presence of botulinum spores in centrifugal and gravity separated creams

C. botulinum spores of proteolytic types A and B were not found neither in 181 nor in 22 samples of centrifugal and gravity separated creams, respecti vely. These results were obtained by an ELISA-type immunoenzymatic method u sed to estimate the presence of botulinum toxins types A and B in enrichmen t cultures. In addition, the detection of C. botulinum spores was also carr ied out on a selective medium. Typical colonies from 104 centrifugal separa ted creams were isolated. These botulinum-like isolates were not identified as C. botulinum by specific PCR, while they showed identical biochemical c haracteristics of the toxigenic species. Since all enriched cultures from r aw gravity separated creams, which resulted negative both for toxin product ion and for presence of botulinum-like spores,,showed lower pH, an improvem ent of the culture conditions was carried out. After modifications, botulin um-like spores were found in all the samples, while toxin production was co nfirmed negative. The meaning of the recovery of clostridia similar to C. b otulinum, and the performance of the analytical protocol used have been dis cussed.