Glossary
Two-hour rule
USDA guidance to refrigerate perishable cooked food within two hours, or within one hour above 90 degrees F.
The two-hour rule is USDA food safety guidance stating that perishable cooked food should not sit at room temperature for more than two hours before it goes into the fridge or freezer, since that window is roughly how long it takes bacteria to multiply to unsafe levels between 40 and 140 degrees F. On a hot day above about 90 degrees F, that window shrinks to one hour.
For meal prep, this means planning your cooling and storage step as part of the cooking session rather than an afterthought. Cooking a large batch, letting it sit out to cool completely, and then packing containers can easily eat up most of the two hours, especially with a big pot of soup or chili that holds heat for a long time.
The most common mistake is leaving a large pot of hot food to cool as one mass rather than dividing it into shallow containers first, which slows cooling dramatically and risks crossing the two-hour window before the food is even fully cold. Splitting food into smaller portions right after cooking is the simplest fix, and it pairs naturally with labeling containers as soon as they go into the fridge.