2 hours – the time food can safely stay a room temperature before it needs to be refrigerated or frozen.
2 inches – the depth of food in a pan so it can cool down quickly in the fridge. If necessary store in mutiple shallow pans to speed chilling and recombine the food into a larger batch when cold.
4 days – the longest safe amount of time you can keep leftovers in the fridge. The exception to the 4 day rule is stuffing and gravy which should be used or discarded in 2 days.
0 seconds – food that falls on the floor should not be eaten. The 5-second rule is a myth. As soon as food touches a dirty surface it can pick up bacteria.