Heat Injury and Recovery of Vegetative Cells of Clostridium botulinum Type E

Vegetative cells of Clostridium botulinum type E (Tenno) were heated at 40.5 C in a prereduced peptone-yeast extract broth (PY). During the heating period, cell numbers remained essentially constant for 3 h as indicated by roll tube counts in PY agar (PYA); however, injury and recovery from injury were observed when the cells were enumerated using PYA containing either 0.06 or 0.07% bile salts.