THERMAL INACTIVATION OF CLOSTRIDIUM-BOTULINUM TOXINS TYPE-A AND TYPE-B IN BUFFER, AND BEEF AND MUSHROOM PATTIES

To determine the time-temperature relationships for the inactivation of botulinal toxins, crude toxins were prepared from 3 type A strains (62A, 73A, V141) and 2 type B strains (Beans-B and 999B). Toxins were diluted to 6700-32,000 mouse LD50 units/0.5 ml in beef and mushroom patties and in 0.1 M phosphate buffer at pH 6.05 and 0.1 M acetate buffer, pH 5.0, and were heated at temperatures from 67.8-80.0.degree. C. In the patties, inactivation times ranged from 53.15 min to 0.62 min and from 51.20 min to 1.08 min for the most thermostable type A (73A) and type B (Beans-B) toxins, respectively, whereas significantly less time was required in phosphate buffer.