Food and environmental aspects of infant botulism in California.

In an effort to identify vehicles by which Clostridium botulinum spores might have reached the intestine of patients with infant botulism, 555 samples of foods, drugs, and environmental specimens were examined. Of the food items, C. botulinum was only found in nine of 90 (10%) honey specimens. Five patients had been exposed to honey that contained C. botulinum, and ingestion of honey was found to be a significant risk factor for type B infant botulism (P = 0.005). In addition, C. botulinum was isolated from five samples of soil (three from case homes, two from control homes) and from vacuum cleaner dust from one case home. In every instance in which C. botulinum was isolated from a specimen of honey, soil, or duct associated with a case of infant botulism, the type of toxin (A or B) in the honey, soil, or dust isolate matched the type of toxin of the organism recovered from the infant. Isolation of C. botulinum from the soil of homes of control infants emphasizes the ubiquitous distribution of and exposure to this organism and suggests that host factors are important in the development of illness. Prevention of infant botulism will depend on the identification of these host factors, as well as on the identification of other vehicles that, like honey, may convey C. botulinum spores to susceptible infants.