Enterotoxin was extracted from sporulated cells of Clostridium perfringens type A and purified by gel and ion exchange chromatography. A single protein band was obtained after electrophoresis of the toxin on cellulose polyacetate, and a single precipitin line after immunodiffusion against crude antiserum. Disc gel electrophoresis resulted in the resolution of the toxin into one major and two accessory bands, all biologically active, and into a few faint bands which had no measurable biological activity and constituted less than 3% of the total protein. The two accessory enterotoxin bands appeared to be derived from the major band as a result of ion exchange chromatography.The ultraviolet absorption spectrum of the purified enterotoxin was characteristic for proteins. The toxin was essentially free of nucleic acids, fatty acids, lipid phosphorus, and reducing carbohydrates. Its apparent molecular weight was 36 000 ± 4000, the Stokes radius was 2.6 mμ, and the isoelectric point was at pH 4.3. The purified toxin was enterotoxic in ligated intestinal loops of rabbits and had a specific toxicity of about 2000 mouse MLD/mg N.

Extracts from sporulated cells of Clostridium perfringens type A, capable of producing diarrhea and fluid accumulation in ligated intestinal loops of rabbits and lambs, also caused erythema in guinea pigs and rabbits when injected intradermally. None of the known toxins of C. perfringens type A contributed significantly to the skin reaction. Both the enteropathogenic and erythemal activities were sensitive to heat, nondialyzable, precipitable with ammonium sulfate, antigenic, and insensitive to treatment with C. perfringens type A antitoxin. The enteropathogenic activities varied widely between three individual strains but showed a direct relationship to their erythemal activities. Both activities were eluted as a single fraction on a column of Sephadex G-100. It was concluded that the enteropathogenic and erythemal activities are due to a single component of sporulated C. perfringens cells.The assay of the enteropathogenic factor by the skin test is rapid, reproducible, accurate, and about 1000 times as sensitive as the intestinal loop technique in rabbits.

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When pH was controlled during the growth of C. perfringens type C there was an increase in toxin but not in cells. The increases in toxin over that obtained at uncontrolled pH were 3-, 20-, 70-, and 4-fold, for alpha, beta, delta, and theta toxins respectively. pH control did not increase the yield of kappa toxin. Optimum pH was 6.7 for alpha, 7.5 for beta and theta, and 7.5–8.0 for delta. The maximum yields of toxins at optimum pH were 90 MLD of alpha, 100,000 MLD of beta, 2000 hemolytic units of delta, and 4000 hemolytic units of theta. Mu and nu toxins were not produced by the strain of type C used.

A total of 150 honey, 43 syrup and 40 dry cereal samples were analyzed for Clostridium botulinum spores, each in triplicate quantities of 25 g. The foods were sampled randomly, except for two lots of honey which were potentially associated with illness. Botulinal spores were detected in a sample of honey associated with infant botulism and in a single sample of rice cereal.