How Long Can Food Sit Out?

The 2-hour rule, in plain terms

The USDA food safety rule is short. Perishable food can sit at room temperature for up to 2 hours. After that, refrigerate it or throw it away. When the air temperature is above 90 F, the safe window drops to 1 hour.

The rule exists because of bacteria. Between 40 F and 140 F, the range food safety experts call the danger zone, bacteria multiply fast. Two hours is the point where enough of them can build up to make a healthy person sick. Above 90 F, the heat speeds that growth, so the safe window halves.

This applies to meat, poultry, fish, eggs, dairy, cooked rice, casseroles, cut melon and anything with a creamy dressing or filling. It does not apply to shelf-stable foods like bread, cookies, crackers, chips and whole fruit, which can sit out far longer. The calculator above checks your time and temperature against the rule and tells you whether the food is still safe.

What counts as perishable food

The 2-hour rule only matters for food that can grow bacteria. Sorting your spread into two groups makes the whole thing simple.

• Perishable, follow the rule: raw and cooked meat, poultry, seafood, eggs and egg dishes, milk and cheese, yogurt, cooked rice and pasta, potato and pasta salad, casseroles, cut fruit and vegetables, and anything with mayonnaise or cream.
• Shelf-stable, no clock: bread, crackers, cookies, chips, pretzels, nuts, whole fruit, whole vegetables, honey, jam and vinegar-based pickles.

A few items sit in between. A butter-based cake with no cream is fine for hours. A cream cheese frosting is not. A jar of opened mayonnaise is acidic enough to be shelf-stable, but a bowl of potato salad made with it is not, because the potatoes and the moisture give bacteria a place to grow.

When you are not sure which group an item belongs to, ask whether it would spoil on a warm counter. If it would, treat it as perishable and start the clock the moment it comes out of the fridge or off the heat.

Worked example: a picnic at 95 F

Say you set out a potluck at 1:00 pm on a 95 F day and you are deciding what to keep at 2:15 pm.

• Temperature is above 90 F, so the safe window is 1 hour.
• By 2:00 pm the food had been out for 1 hour, which is the limit.
• At 2:15 pm, potato salad, deviled eggs, sliced ham and the creamy coleslaw have all been out for 1 hour and 15 minutes, which is past the window.

The shelf-stable items are a different story. The bread, the chips and the cookies can stay out. The cut watermelon cannot, because once you cut it, it becomes perishable and the 1-hour limit applies.

Here is the part people resist: moving the salads into the fridge at 2:15 does not rescue them. The bacteria have already grown. The USDA advice is to throw the food out. On a hot day, the safer plan is to set out small portions and keep the rest in a cooler, refilling as you go. That way nothing crosses the 1-hour mark.

The clock on common foods

This table shows how long different foods can stay out, based on the USDA rule. The limit depends on the air temperature, not the food, so the last two columns are the ones to read.

After the food is chilled, most cooked leftovers keep for 3 to 4 days in the fridge, and reheat to 165 F. The USDA page on handling take-out and leftover food covers the 2-hour rule and the 4-day limit together.

The danger zone: 40 F to 140 F

The 2-hour rule is a rule about temperature. Bacteria that cause food poisoning grow fastest between 40 F and 140 F. Inside that band they can double roughly every 20 minutes, so a small number becomes a large number in a few hours.

Cold slows them down. Your fridge should hold 40 F or below, and the freezer should be at 0 F. Heat above 140 F stops them, which is why hot food on a buffet is kept hot rather than just warm. The safest setup at a party is to keep cold food on ice and hot food in a chafing dish, so nothing sits in the middle.

A food thermometer removes the guesswork. Keep one in the fridge to confirm it holds 40 F, and use a probe thermometer to check that reheated leftovers reach 165 F. The FDA guide to cutting food waste safely explains how to tell the difference between food you can save and food you should toss, and the CDC food safety pages walk through the four steps of clean, separate, cook and chill.

What to do when food has sat out too long

If the calculator says your food is past the window, the safe answer is to throw it out. That is a hard rule to follow when the food looks and smells fine, but looks are not a test. The bacteria that cause most food poisoning do not change the taste, smell or texture of food.

A few practical habits cut down on waste without taking a risk.

• Chill fast. Split big pots of soup or chili into shallow containers so they cool quickly. A deep pot can sit warm for hours in the fridge.
• Serve in smaller amounts. Put out what people will eat in an hour, and keep the rest cold or hot until you refill.
• Use a cooler for the drive. Food on the way home from the store or a party counts toward the clock.
• Label and date leftovers. Eat them within 3 to 4 days, and reheat to 165 F.

If you are ever unsure whether an item crossed the line, the cost of tossing it is small next to a day or two of food poisoning. When in doubt, throw it out.