Number of Clostridium botulinum Spores in Honey

A dialysis-enrichment culture method for detecting Clostridium botulinum spores in honey is described. The method was used to survey 55 honey samples representative of 53 lots being sold at retail and 186 honey collections from 154 individual producers. Based on finding the organism in at least one of three 25-g test portions of a sample, one type A and one type B positive were found among the retail samples. Type A spores were found in collections of five different producers and type B in those of five others. Five of 13 different lots from one producer were positive for type A spores. One producer sample had both types A and B spores. Maximum most probable number by the five-tube method was seven botulinum spores (upper 95% confidence limit of 17) per 25 g of sample.