Whole-muscle roasts (like a beef roast) may be cooked using lower temperatures held for longer times. This is allowed because:

Explanation

Cooking safety depends on the combination of temperature and time: a lower internal temperature held for a longer time can destroy pathogens as effectively as a higher temperature held briefly, which is why roasts have approved lower-temperature and longer-time tables. This does not mean roasts are pathogen-free or exempt from rules. Time is a genuine safety factor, not irrelevant.