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, respectively.These results were obtained by an ELISA-type immunoenzymatic method used to estimate the presence of botulinum toxins types A and B in enrichment cultures. In addition, the detection of C. botulinum spores was also carried out on a selective medium.Typical colonies from 104 centrifugal separated creams were isolated.These botulinum-like isolates were not identified as C. botulinum by specific PCR, while they showed identical biochemical characteristics of the toxigenic species. Since all enriched cultures from raw gravity separated creams, which resulted negative both for toxin production and for presence of botulinum-like spores, showed lower pH, an improvement of the culture conditions was carried out. After modifications, botulinum-like spores were found in all the samples, while toxin production was confirmed negative. The meaning of the recovery of clostridia similar to C. botulinum, and the performance of the analytical protocol used have been discussed.