A common guideline is that food needing temperature control can be out of temperature control for up to 4 hours before it must be discarded, and in food businesses that can require written procedures. A closed, full walk-in may stay cold longer than that, but you cannot count on it. Measure the food, keep the door closed and follow your health department's direction.
When the compressor stops, the clock starts. The box does not warm instantly, and how quickly it warms depends on several things. That is why one number cannot cover every kitchen.
What changes the answer
| Factor | Effect |
|---|---|
| How full the box is | Full boxes hold cold longer |
| Door openings | Every opening lets cold air out |
| Outside temperature | Hot Mississippi summers speed warming |
| Box size and insulation | Better insulation slows the rise |
| Starting temperature of the food | Colder food gives more time |
| Type of food | Some foods spoil faster than others |
What to do in the first minutes
- Note the time. Write down when you found the problem.
- Keep the door shut. Every opening costs time.
- Check the simple causes. Power, breaker, disconnect. See no power.
- Probe the warmest food. Record temperatures.
- Call for repair quickly, and plan where food will go.
- Move the most perishable items to another cold space if the fix will take long.
The 4-hour idea
The FDA Food Code describes time as a public health control, where food needing temperature control may stay out of control for a limited period, commonly 4 hours, if you follow written procedures and mark when it left control. Without a procedure, an inspector may treat food above 41 degrees as a violation. Ask your health department how it applies to your permit.
When to throw food out
- Food that has been above 41 degrees longer than allowed.
- Food you cannot account for, with no reading or time.
- Anything with off smell, slime or unusual appearance.
- Ready-to-eat items that touched drips from warm raw food.
When in doubt, throw it out. The cost of a discard is small compared with an illness. See what to throw away after an outage and the TCS foods page.
Prevent the emergency
Most failures give warning signs. A log, regular maintenance and a repair contact reduce the risk. For outages, see storm recovery and storm prep.
Freezers behave differently
A full freezer that stays closed holds its temperature far longer than a cooler because frozen food acts as thermal mass. Even so, do not assume. Check the food for ice crystals and hardness, and keep readings. If the freezer has warmed and food has thawed, do not refreeze it without direction from your health department.
Ice can also help in an emergency. Bagged ice or frozen gel packs in insulated containers can protect high-risk items while you wait for repair. Keep raw items separate from ready-to-eat items in the coolers, just as you would on the shelves.
Questions about failures
Does a full cooler stay cold longer?
Generally yes, because cold food helps hold temperature, but you should still measure rather than assume.
Can I refreeze thawed food?
It depends on how warm it got and for how long. In a food business, follow your health department's direction.
Who decides what is safe?
The person in charge decides under your food-safety plan, and the inspector can overrule. Ask the health department when unsure.