抄録
Since 1952, the year of first outbreak of botulism in Japan reported by NAKAMURA et al., about twenty cases of the outbreak have been described in the literature by 1956. All these outbreaks have proved to be of TYPE E and have been caused by such fish products infected with Cl, botulinum TYPE E as “IZUSHI” prepared from raw fish.
In Europe and America, about ten cases of type E botulism except one have also been caused by fish products. DOLMAN (1950) stated that fish is one of the most possible vehicle for type E botulism.
We have undertaken an investigation of the growth and the toxin production of Cl. botulinum TYPE E in fish flesh in order to clearify the outbreaks of type E botulism through the partake of fish products and further to find a preventive procedure for this food.
The present report deals with the correlation between the growth and oxidation-reduction potential in fish flesh and the results obtained are as follows.
1. The sterilized media prepared by various kinds of fish, produced a negative potential to offer a suitable condition for the growth of type E spore.
2. In the squid medium, the growth was partially inhibited owing to the positive potential, which seemed to be resulted from the oxidation of sulfhydryl groups by trimethylamine oxide in squid muscle during heat sterilization.
3. Sulfhydryl compounds such as cysteine and thioglycolic acid were rapidly oxidized by trimethylamine oxide at 100°C., but not at 37°C. within one hour.
4. Cl. botulinum TYPE E was able to reduce trimethylamine oxide which was added to the previously sterilized anaerobic medium.
5. In the course of autolysis and putrefaction of fish flesh, the potential fall rapidly to give an
anaerobic condition to the type E spore, and then the growth and toxin production was observed.
