Answer: The type sterilization that was used and how well it was performed
Step-by-step explanation:
If there's a phone call from the sterilization monitoring company that the last spore test sent has failed, to determine the possible cause, I'll have to type sterilization that was used and how well it was performed.
The sterilization technique used will be analysed, and there'll also be a check for possible human errors. Once thus is done, the possible reason for the failure of the last spore that was sent can then be determined.