Use of immunofluorescence and animal tests to detect growth and toxin production by Clostridum botulinum type E in food.

The appearance of Clostridium botulinum type E organisms and of toxin in experimentally inoculated packages of turkey roll was followed to study the time relationship between the presence of vegetative cells and the demonstration of toxin. The presence of vegetative cells was determined by immunofluorescence, and animal tests were used to assay toxin production. Growth initiated from detoxified spores of C. botulinum type E resulted in toxin formation within 24 hr. Presence of fluorescing vegetative cells and of toxin coincided from 1 to 14 days of incubation. Beginning with the next testing date, day 21, differences were observed. Toxin could be detected for a longer time than vegetative cells. Neither toxin nor organisms could be found after 56 days of incubation. The mouse lethal dose tests (MLD per gram of turkey roll) showed fluctuations in the amount of toxin present throughout the period of testing. Maximal amounts of toxin were present during the period when fluorescing organisms were also more numerous. The applications of immunofluorescence in the study and in the diagnosis of botulism is discussed.