What Is the Temperature to Kill Bacteria in Food?

What is the temperature to kill bacteria? For the bacteria that cause most food poisoning, 165°F kills them almost instantly. That is why poultry, stuffed foods and leftovers reheated for hot holding all have a 165°F limit in the FDA Food Code. But 165°F is not the only safe number. Bacteria die faster the hotter it gets, so a lower temperature held for longer does the same job: 145°F for 15 seconds for fish, 155°F for 17 seconds for a burger, or 130°F for nearly two hours for a rare roast.

Two things heat does not fix. Some bacteria, like Clostridium perfringens and Bacillus cereus, form spores that survive cooking. Others, like Staphylococcus aureus, make toxins that stay in food even after the bacteria are dead. That is why the cooling, holding and hygiene rules exist alongside the cooking limits.

This guide gives the chart, explains the science in plain terms, and covers reheating, the rule where kitchens most often misunderstand what heat can and cannot do. Sources: the FDA Food Code 2022 and the FDA Bad Bug Book.

What is the temperature to kill bacteria? The chart

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Why time matters as much as temperature

Heat kills bacteria by damaging their proteins and membranes. The damage is not instant at moderate temperatures; it builds over time. Food scientists describe this with a D-value, the time at a given temperature that kills 90 percent of a population. A 7-log reduction, which kills 99.99999 percent, is the target for Salmonella in poultry.

That is why the Food Code tables trade time for temperature. At 145°F a roast needs about 4 minutes; at 130°F it needs 112 minutes. Sous vide cooking uses the same tables, which is why it needs a written plan; see the sous vide HACCP plan.

Bacteria that heat does not fully control

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This table is the reason a kitchen can cook every item to the right temperature and still make people sick. Heat is one control in a system; the others are in our guides to hot food in the fridge and TCS food.

Reheating: the temperature to kill bacteria in leftovers

The 165°F rule applies when all of these are true:

• the food is TCS (time/temperature control for safety)
• it was cooked and then cooled in your establishment
• it is being reheated to be hot held, such as in a steam table, soup well, hot box or chafing dish

It does not apply when:

• the food is reheated for immediate service to one customer, such as a single portion heated to order (3-403.10)
• the food is a commercially processed, ready-to-eat product from an intact package, which only needs 135°F for hot holding (3-403.11(C))
• the food is an unsliced roast cooked under the roast rules, which can be reheated using the original roast oven parameters (3-403.11(E))

Read the code section for the exact conditions.

The Food Code reheating rules in a table

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Why the rule exists

Cooked food that is cooled and stored is never sterile. Spores of Clostridium perfringens and Bacillus cereus survive cooking, and if cooling was even a little slow they can grow. Listeria can grow slowly during refrigerated storage. Reheating to 165°F reduces vegetative bacteria before the food spends hours in hot holding.

The 2 hour limit matters as much as the temperature. Food reheated slowly spends time in the warm range where bacteria grow fastest. A pot of soup put in a steam table cold and left for 3 hours to warm up may grow more bacteria during reheating than it had before.

Reheating does not fix every problem. Some toxins, such as the emetic toxin of B. cereus and the toxin of Staphylococcus aureus, are heat stable. That is why cooling and cold storage controls still matter. See food cooling rules.

How to check reheating temperature

Use a calibrated probe thermometer. For soups and sauces, stir and then probe in the center. For solid foods, probe the thickest part. For a full hotel pan, probe several spots, because the corners heat faster than the middle. Hold the reading at 165°F or above for at least 15 seconds. See the thermometer calibration log for keeping your probe accurate. USDA FSIS has a useful page on using food thermometers.

Reheating versus cooking temperatures

Reheating to 165°F is separate from the cooking temperatures. Chicken is cooked to 165°F under 3-401.11, so it is easy to confuse the two. Fish is cooked to 145°F, but once cooked, cooled and reheated for hot holding, it also needs 165°F. The reheating temperature does not depend on the original cooking temperature of the food. See the HACCP critical limits chart for both sets of limits side by side.

Common reheating mistakes

• Reheating in the steam table. The most frequent violation.
• Reheating too much at once. A full stockpot takes too long. Reheat smaller batches.
• Probing only the edge. The center is the coldest.
• Mixing new and old batches. Add new food to a clean pan, not on top of leftovers.
• Reheating more than once. Not banned by the Food Code, but each cycle adds risk. A one-reheat rule is simple and common.
• Not logging. If reheating is a CCP, the log is the evidence.

Equipment for reheating

Stovetop

The most common method. Use a heavy pot and stir to avoid scorching. Heat a smaller amount at a time if needed. Probe the center after stirring.

Oven

Good for casseroles, braised meats and items in hotel pans. Cover to hold moisture. Probe the center of the thickest piece.

Steam kettle or tilt skillet

Fast for large batches of soup, chili and sauces.

Combi oven

Combines steam and convection heat. Fast and even for many foods.

Microwave

Allowed under 3-403.11(B) with specific conditions:

• heat to at least 165°F in all parts
• rotate or stir during heating
• cover to retain heat
• let stand covered for 2 minutes after heating

Microwaves heat unevenly, so the stand time and stirring matter. Probe several spots.

Not suitable: steam tables, heat lamps, holding cabinets

These hold food that is already hot. They do not have the power to reach 165°F within 2 hours for most foods. Using them to reheat is a common violation.

How to log reheating

A reheating log is short:

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If reheating is a CCP in your plan, log every batch. Some kitchens combine reheating and hot holding on one log, with the first entry being the reheat temperature. Blank logs are on the free logs page.

Corrective actions when reheating falls short

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See HACCP corrective actions examples.

Reheating as a critical control point

In most restaurant HACCP plans that use the cook, cool, reheat process, reheating is a CCP. It is often the last step before hot holding that reduces bacteria. The plan entry:

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The NACMCF HACCP guidelines describe how to decide whether a step is a CCP. See critical control point examples.

Reheating for immediate service

A cook heats one portion of yesterday's chili in a sauté pan to order and puts it straight on a plate. Under 3-403.10 this can be served at any temperature, because it is going directly to the customer and will not sit in hot holding. In practice most kitchens still heat it thoroughly because customers expect hot food, but the 165°F rule does not apply.

If that same chili were heated in a batch for the lunch steam table, the 165°F rule would apply.

Reheating commercially processed foods

Canned chili, frozen soups from a manufacturer, packaged precooked sausages and similar products that come from a commercial processor in an intact package only need to reach 135°F for hot holding. The manufacturer's process already controlled the hazards. Once you open the package and the food has been handled, cooled and stored in your kitchen, treat it like your own cooked food.

Reheating roasts

Unsliced roast beef, corned beef and pork roasts cooked under the roast rules can be reheated for hot holding using the same oven time and temperature used to cook them. This keeps a rare roast rare. Once sliced, the roast is treated like other cooked food.

A worked example: Monday chili, Wednesday lunch

1. Monday: chili is cooked, cooled using shallow pans and an ice bath (logged), labeled with the date and stored at 41°F.
2. Wednesday, 9:30 a.m.: one pan of chili is moved to the range in a heavy pot. The start time is recorded.
3. 10:05 a.m.: after stirring, the chili reads 168°F in the center. Held for 15 seconds. Recorded.
4. 10:10 a.m.: chili is moved to a preheated steam table well at 135°F or above. Hot holding checks begin.
5. 2:30 p.m.: leftover chili is discarded under the house rule of one reheat only.

This is the cook, cool, reheat process most restaurants run every day. See HACCP flow diagram examples.

Reheating on buffets and in self-service

Buffets often run all day with food refreshed from the kitchen. Every pan that goes out should be at temperature before it leaves the kitchen: 165°F if it was reheated, or straight from cooking if it was just made. Never top up a buffet pan with reheated food added to food that has been sitting out. Bring a fresh pan and take the old one back. If a buffet pan drops below 135°F, follow your plan, which usually means reheating in the kitchen within the time allowed or discarding.

Self-service soup kettles are a special case. Many are sold as "rethermalizers" that can reheat from cold. If the manufacturer states the unit can bring food to 165°F within 2 hours, and you have checked that it does with a full load, it may be acceptable. Test it and record the result before relying on it.

How reheating fits with hot holding

After reheating to 165°F, food goes into hot holding at 135°F or above. See cold holding vs hot holding temperatures. If the food then drops below 135°F, your plan decides whether it can be reheated again or must be discarded. Many plans allow one reheat to 165°F if the food was below 135°F for less than 2 hours.

Reheating different foods: practical notes

Each food behaves differently, and the method that works for soup will not work for lasagna.

Soups and broths reheat quickly and evenly if stirred. The risk is a cook putting a full 22 quart container straight into a soup well. Reheat on the range in a pot, then transfer.

Thick stews, chili and beans scorch on the bottom before the center is hot. Use moderate heat, stir often, and add a small amount of liquid. Reheat in smaller pots if needed.

Gravy and cream sauces can break if heated too fast. Whisk while reheating. Gravy is a classic C. perfringens vehicle, so take reheating seriously.

Cooked rice dries out. Add water, cover and steam or microwave with stirring. Reheat only what you need for the next few hours.

Casseroles and lasagna are dense and heat slowly in the center. Reheat covered in the oven, probe the center, and consider cutting into portions first so heat reaches the middle faster.

Whole cuts of braised meat reheat better in their braising liquid, covered, in the oven. Slice after reheating if you can, or reheat slices in hot liquid.

Mashed potatoes need gentle heat and stirring. Add milk or butter to restore texture.

Pulled pork and shredded chicken reheat well in a covered pan with some liquid.

For each item you reheat regularly, write a short note in your plan: the method, the batch size and roughly how long it takes to reach 165°F. Time the first few batches so you know your method will meet the 2 hour limit with room to spare.

What inspectors look for

Inspectors often walk the line and probe steam table food. If a pan of soup reads 120°F, they will ask whether it is being reheated or held. If the answer is "it's warming up," that is usually a violation. They may also ask to see the reheating log and how long it takes to reheat a batch. See the health inspection food safety checklist.

Reheating and food quality

Reheating to 165°F is about safety, but it also affects quality. A few tips:

• Add a little liquid to soups and sauces to prevent scorching.
• Cover pans in the oven to prevent drying.
• Reheat rice with a splash of water and a lid.
• Undercook vegetables slightly when cooking ahead, so they hold up after reheating.
• Reheat fried foods in an oven or fryer, not a microwave, to keep them crisp.

Put kill steps into your plan

Every kill step in your kitchen, cooking, reheating and sous vide, needs a limit, a check and a corrective action. The HACCP plan builder writes the Food Code number for each step and prints logs. See also the ground beef temperature chart. The first process is free; the plan is a draft for your health department to review.

Frequently asked questions

What is the temperature to kill bacteria in food?

165°F kills common foodborne bacteria almost instantly. Lower temperatures work with longer hold times, such as 145°F for 15 seconds or 130°F for 112 minutes for some roasts.

Does boiling kill all bacteria?

Boiling at 212°F kills active bacteria, but not all bacterial spores, and it does not destroy toxins such as Staphylococcus aureus enterotoxin.

Does freezing kill bacteria?

No. Freezing stops growth but most bacteria survive and start growing again after thawing. Freezing does kill parasites in fish when done to Food Code limits.

Why must leftovers be reheated to 165°F?

The Food Code requires food reheated for hot holding to reach 165°F within 2 hours to kill bacteria that may have grown during cooling and storage.