I was reading the food safety section of MC and it mentioned about officials deciding to issue recommendations only by temperature, not temperature and time. It occurred to me that one possible reason for this is the ability to regulate it. Its quite easy for an inspector to check that foods have been cooked to the proper temperature. Checking that they have been held at a lower temperature for a minimum amount of time is much trickier. Unless they witness the whole process, they have no way of knowing it was actually held at that temp for that amount of time.
