This became inevitable at some point.
I wish we had more information. Did this employee have proper training? Were they properly briefed on the importance of refrigeration? Were they ordered or pressured to do this? Were they overworked and dead on their feet? We can’t out rule the possibility that they were a scapegoat for the company, considering that the action taken was to fire one employee and not investigate anyone else.
People should consider these things before calling for blood.