Thermal Inactivation of Clostridium Botulinum Toxins Types a and 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 three type A strains (62A, 73A, V141) and two type B strains (Beans‐B and 999B). Toxins were diluted to 6,700‐32,000 mouse LD, units/0.5 ml in beef and mushroom patties and in 0.1 M phosphate buffer, both at pH 6.05, and 0.1M acetate buffer, pH 5.0, and were heated at temperatures from 67.8‐80.0°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.