USDA's three rules
Per USDA Food Safety and Inspection Service, three rules govern food safety during a power outage. Memorize them.
- 01
Keep doors closed
A closed refrigerator stays safe for ~4 hours. Each opening costs roughly 30 minutes of safe time. A closed full freezer stays safe ~48 hours; half-full, ~24 hours.
- 02
40°F is the danger line
Once perishables sit above 40°F for more than 2 hours, USDA says discard them. This applies to meat, poultry, fish, eggs, dairy, and leftovers — not to condiments, hard cheese, or whole produce.
- 03
Verify, don't taste
Use an appliance thermometer to confirm temps. Bacterial pathogens don't change taste or smell — tasting is not a safety check, ever.
What to do with fridge contents
Group your fridge into three categories — discard, check, keep — based on USDA guidance.
| Category | Verdict | Examples |
|---|---|---|
| Raw meat, poultry, seafood | Discard after 2 hrs above 40°F | Ground beef, chicken, fish fillets |
| Cooked meat & leftovers | Discard after 2 hrs above 40°F | Casseroles, soups, cooked pasta |
| Dairy (soft) | Discard after 2 hrs above 40°F | Milk, cream, yogurt, soft cheese |
| Eggs & egg dishes | Discard after 2 hrs above 40°F | Fresh eggs, quiche, custards |
| Hard cheese | Keep — generally safe | Cheddar, Swiss, Parmesan |
| Butter & margarine | Keep — generally safe | Stick butter, soft margarine |
| Whole produce | Keep — generally safe | Apples, oranges, whole carrots |
| Cut produce | Discard after 2 hrs above 40°F | Sliced melon, cut salad greens |
| Condiments | Keep (most) | Ketchup, mustard, jam, pickles |
| Mayo & tartar sauce | Discard after 8 hrs above 40°F | Opened mayo jar, deli salads |
Source: USDA Food Safety and Inspection Service, “Food Safety During Power Outages.”
What to do with frozen food
Frozen food is more forgiving than refrigerated. USDA's rule: if it still has ice crystals or is at or below 40°F, it's safe to refreeze. Quality may suffer, but safety is intact.
Per USDA: a full freezer stays safe ~48 hours; half-full, ~24 hours. Mass equals thermal inertia — the more frozen food packed inside, the longer it holds. Keep your freezer at least 75% full year-round if outages are common.
Can you refreeze it?
USDA's three-part test:
Still has ice crystals
Yes, refreeze. The food never fully thawed — it's safe.
Thawed but still cold (≤40°F)
Refreeze for safety, but use sooner — quality and texture will suffer. Cook before refreezing where practical.
Above 40°F for over 2 hours
Discard. Bacterial growth has crossed USDA's safety line.