AN IMPROVED MEDIUM FOR DETECTION OF CLOSTRIDIUM BOTULINUM TYPE E

An enrichment medium containing trypticase, peptone, glucose, yeast extract, and 1 mg of trypsin/ml (TPGYT) has been developed for detection of Clostridium botulinum type E. It was designed to potentiate toxin as produced and destroy the boticins of competing type E variants in cultures of foods and environmental materials. Samples of 227 sediments and 283 shellfish from different areas of the continental United States yielded 74 more positive cultures of type E in TPGYT than in the same medium free of trypsin. Type E toxin was detected in all smoked fish inoculated with 4 to 100 type E spores per fish in TPGYT. Incorporation of trypsin into the medium caused no reduction in type A or proteolytic type B toxin production from spore inocula. Toxins of nonproteolytic types B and F in pure culture were fully potentiated in the trypsin-containing medium.