All of the following statements regarding Clostridium tetani are true, except

The resistance of tetanus spores to heat appears to be subject to strain differences. Most are killed by boiling for 10-15 mins but some resist boiling for up to 3 hrs. Autoclaving at 121degC for 20 mins ensures complete removal of spores. Reference: Textbook of Microbiology; Anathanarayan and paniker's; 10th edition; Page no: 265