What Storing and Reheating Leftovers Is, and Why It Matters
Storing and Reheating Leftovers: what it is, why it matters, and what published guidance actually asks of you.
Bacteria grow fastest between 40°F and 140°F (4°C to 60°C), and some produce toxins that reheating does not destroy, so timing matters as much as temperature.
Key takeaways
- Refrigerate within: 2 hours of cooking, or 1 hour if the room or outdoors is above 90°F (32°C)
- Use refrigerated leftovers within: 3 to 4 days
- Most useful single change: Divide large amounts into shallow containers so they cool quickly in the refrigerator.
- Commonest mistake: Leaving food out to cool on the counter for hours before refrigerating it.
- See a doctor if any of the signs under "When to speak to a doctor" below apply to you.
The short answer
How to cool, store and reheat cooked food so bacteria do not have time to multiply.
Where it fits
This is part of Food Safety. What follows is what the guidance says, and then what that looks like in practice.
The numbers, in one place
| Measure | Figure |
|---|---|
| Refrigerate within | 2 hours of cooking, or 1 hour if the room or outdoors is above 90°F (32°C) |
| Use refrigerated leftovers within | 3 to 4 days |
| Reheat to | 165°F (74°C); bring sauces, soups and gravies to a rolling boil |
| Frozen leftovers | safe indefinitely at 0°F (-18°C); best quality within about 3 to 4 months |
| The danger zone | 40°F to 140°F (4°C to 60°C) |
What that means in practice
What that looks like in practice:
- Divide large amounts into shallow containers so they cool quickly in the refrigerator
- Label containers with the date you cooked the food
- Thaw frozen leftovers in the refrigerator or microwave and reheat them right away
- Cover food when microwaving and stir halfway through so it heats evenly
What gets people into trouble
The pitfalls worth knowing about:
- Leaving food out to cool on the counter for hours before refrigerating it
- Smelling or tasting food to decide if it is safe; most germs that cause illness do not change taste or smell
- Keeping takeout or party food that sat out longer than 2 hours
Related topics
- What the Guidance Really Says About Meal Planning (Nutrition)
- Batch Cooking: Sorting the Evidence From the Noise (Healthy Recipes)
- Food and Water Safety Abroad: Sorting the Evidence From the Noise (Travel Health)
- Storing Medicines: What Published Guidance Supports (Medicines Safety)
Where to go next
- Storing and Reheating Leftovers: Common Questions Answered
- Storing and Reheating Leftovers: Just the Figures
- Storing and Reheating Leftovers — the reference entry
- Food Safety: The Complete Guide
- Food Recalls: Sorting the Evidence From the Noise
- Raw Milk: Sorting the Evidence From the Noise
When to speak to a doctor
See your doctor if vomiting or diarrhea lasts more than a few days, comes with a high fever or blood, or affects someone who is pregnant, very young, older or has a weakened immune system. Call 911 for severe dehydration, confusion or fainting.
Where this comes from
How this page was put together
Every figure, recommendation and warning above is taken from the guidance named in Where this comes from. Nothing on this page is inferred, summarized or generalized beyond what those bodies publish: where they give a number, it is their number, and where they are silent, so are we. Pages are rebuilt whenever the underlying record changes. Sign-off by a named clinician, where it has happened, is shown at the top of the page along with the date.
Medical disclaimer
This article is general information, not medical advice. It cannot account for your own history, medication or circumstances. Always speak to your doctor, pharmacist or another qualified health professional before making changes that affect your treatment, and never delay seeking medical advice because of something you have read here. In an emergency, call 911.
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