Cooking Temperatures That Kill Bacteria: USDA Numbers by Food
Daniel Gritzer brings hands-on cooking experience and a strong understanding of ingredients, techniques, and food science. His approach connects what happens in the kitchen with why it happens, helping readers understand common cooking questions and improve everyday meals.
Quick answer
Cooking food to the right internal temperature kills harmful bacteria, but some bacteria leave behind toxins that high heat may not destroy. The USDA sets minimum safe temperatures from 145°F to 165°F depending on the food. Use a food thermometer to check. If food sat out too long before cooking, toxins may already be present and reheating will not make it safe.
Temperature Is the Only Reliable Safety Check
Harmful bacteria in food are invisible. You cannot see, smell, or taste them. Color, texture, and aroma tell you nothing. Dangerous germs may still be present even if food looks and smells fine. Use a food thermometer to check the internal temperature. That is the only way to know food is safe. Germs like Salmonella, E. coli, and Campylobacter can make you very sick.
The USDA and FoodSafety.gov publish minimum internal temperatures for every major food type. These are not suggestions. They are the temperatures at which harmful bacteria are killed. Cooking below them leaves risk. Cooking to or above them removes it.
Minimum Safe Temperatures by Food Type
The table below lists USDA minimum internal temperatures. Use a food thermometer to check the reading. Insert it into the thickest part of the food, away from bone, fat, or gristle.
| Food | Minimum Internal Temp | Rest Time |
|---|---|---|
| Beef, pork, veal, lamb: steaks, chops, roasts | 145°F (63°C) | 3 minutes |
| Ground beef, pork, veal, lamb | 160°F (71°C) | None required |
| Ground poultry | 165°F (74°C) | None required |
| All poultry (whole bird, breasts, thighs, wings, giblets, stuffing inside poultry) | 165°F (74°C) | None required |
| Eggs and egg dishes (frittata, quiche) | 160°F (71°C) | None required |
| Raw shell eggs | Cook until yolk and white are firm | None required |
| Fish and shellfish (whole or fillet) | 145°F (63°C) | None required |
| Raw ham | 145°F (63°C) | 3 minutes |
| Precooked ham (to reheat) | 165°F (74°C) | None required |
| Leftovers (any type) | 165°F (74°C) | None required |
| Casseroles | 165°F (74°C) | None required |
Why Ground Meat Needs More Heat Than a Steak
A whole steak or roast carries bacteria mainly on its outer surface. Searing the outside kills those surface pathogens, which is why a whole beef steak can be safe at 145°F with a pink center. When meat is ground, surface bacteria get mixed throughout the entire product. A burger patty that looks done on the outside can still harbor live bacteria deep inside.
That is why USDA sets ground beef at 160°F, a full 15 degrees higher than a whole steak. The same logic applies to ground pork and ground lamb. Preventing cross-contamination between raw meat and other foods is equally important. Bacteria spread easily through juices and shared surfaces.
Rest Time: What It Does and Which Foods Need It
Rest time is not about letting meat cool before serving. It is an active safety step. FoodSafety.gov explains that rest time “allows the innermost parts and juices of the meats to become fully and safely cooked.” After you pull the meat off the heat, let it sit for 3 minutes. The internal temperature stays high during that time. That heat keeps killing bacteria in the center of the meat.
Whole cuts of beef, pork, veal, lamb, and raw ham all require a 3-minute rest after reaching 145°F. Poultry and ground meats do not have a separate rest requirement because their higher target temperatures already account for this.
The Danger Zone and the Two-Hour Rule
Bacteria multiply fastest between 40°F and 140°F. FoodSafety.gov calls this the temperature danger zone and recommends keeping hot foods above 140°F and cold foods at or below 40°F. If food sits in this range for more than 2 hours (or 1 hour when the air temperature is above 90°F), bacterial counts can reach dangerous levels.
This matters for cooking because the danger zone is not just a storage concern. Food that spends too long warming up before it reaches a safe cooking temperature, or that cools too slowly after cooking, can accumulate bacteria. Refrigerate leftovers within 2 hours of cooking, using shallow containers so the food chills quickly. Thawing meat on the counter is unsafe for the same reason: the outer surface enters the danger zone long before the center thaws.
When Cooking to a Safe Temperature Is Not Enough
Here is the most important exception to know: cooking kills bacteria, but it does not always eliminate the danger from food that was mishandled before cooking.
Some bacteria can contaminate food when hands are not washed. Foods that are not cooked after handling are especially risky. That includes sliced meats, puddings, pastries, and sandwiches. Staphylococcus aureus is a germ commonly found on skin. It is one example of a germ that can get into food this way. Rice and other prepared foods left too long at room temperature can also become unsafe.
Cooking food to the right temperature kills harmful bacteria. But some bacteria leave behind toxins before you cook the food. Toxins are harmful substances bacteria produce. High heat may not destroy those toxins even after the bacteria are gone. Keeping food out of the danger zone in the first place is the best protection. If food has been sitting at room temperature for more than 2 hours, discard it. Do not assume that thorough reheating makes it safe.
Safe Stop condition: If cooked food has been in the danger zone (40°F to 140°F) for more than 2 hours (or 1 hour above 90°F), discard it. Cooking it again will not make it safe.
The Four-Step Framework: Clean, Separate, Cook, Chill
Temperature control is one part of a four-step system that USDA-FSIS calls the foundation of safe food handling:
- Clean: Wash hands and surfaces often. Wash hands for at least 20 seconds with soap and water before, during, and after handling food.
- Separate: Keep raw meat, poultry, seafood, and eggs away from ready-to-eat foods. Use separate cutting boards and utensils. Learn more about sanitizing cutting boards to reduce cross-contamination risk.
- Cook: Use a food thermometer to verify the correct internal temperature for each food type. Do not rely on color or texture.
- Chill: Refrigerate food promptly. Keep the refrigerator at or below 40°F. Refrigerate leftovers within 2 hours of cooking.
Each step addresses a different failure point. Cooking food to the right temperature does not fix problems caused by cross-contamination before cooking. Proper chilling does not fix food that was never cooked to a safe temperature. You need both steps done right.
Higher-Risk Groups Need Extra Caution
Infants, adults 65 and older, pregnant women, and people with weakened immune systems face more severe outcomes from foodborne illness. Some pathogens are especially dangerous for these groups. Pathogens are germs that cause disease. Listeria can cause fetal death or premature labor in pregnant women. Salmonella is more likely to cause serious complications in older adults and infants. FoodSafety.gov lists these groups specifically so they know to take extra care.
For these groups, the standard minimum temperatures are not optional. Foods like deli meats, hot dogs, and cold cuts should be heated to 165°F or until steaming hot before eating, even if they are labeled ready-to-eat. Cooked chicken storage limits also apply strictly, since Listeria can grow even in the refrigerator over time.
Using a Food Thermometer Correctly
Both FoodSafety.gov and USDA-FSIS specify that temperatures must be measured with a food thermometer. Insert it into the thickest part of the food, avoiding bone, fat, and gristle, which conduct heat differently and give false readings. For thin foods like burgers or chicken breasts, insert the thermometer from the side so the probe reaches the center.
Check the temperature near the end of the expected cooking time, not at the beginning. If the food has not reached the minimum temperature, continue cooking and check again. Do not pull food off the heat and assume it will coast up to the target; always verify with the thermometer before serving.
Illustrative example: You cook a ground beef burger patty. The outside looks brown and the juices run clear, but the center is not hot enough yet. That patty is not safe. Continue cooking until the center reaches 160°F. Checked arithmetic: 160°F converts to (160 minus 32) times 5 divided by 9 = 71.1°C, matching the USDA table.
Frequently asked questions
Does freezing food kill the bacteria in it?
No. Freezing stops bacteria from growing but does not kill them. When food thaws, surviving bacteria can resume multiplying. Cooking to the correct minimum internal temperature is what kills harmful bacteria, not freezing. Always thaw food safely in the refrigerator, in cold water, or in the microwave, then cook immediately.
Can I tell if chicken is cooked safely by checking that the juices run clear?
No. Juice color is not a reliable safety indicator. Chicken can have clear juices and still be undercooked, or pink juices and be fully safe. The only reliable check is a food thermometer reading of 165°F at the thickest part of the meat, away from bone.
If I reheat leftovers to 165°F, are they always safe to eat?
Not always. Reheating to 165°F kills bacteria present at the time of reheating. However, if the food was left in the danger zone (40°F to 140°F) for more than 2 hours before refrigerating, some bacteria may have produced heat-resistant toxins. In that case, reheating does not make the food safe. When in doubt, throw it out.
Do shellfish like shrimp and scallops need a thermometer reading too?
USDA guidance for shrimp, lobster, crab, and scallops says to cook until the flesh is pearly or white and opaque, rather than specifying a numeric temperature. For fish fillets, the target is 145°F or until the flesh is no longer translucent and separates easily with a fork. Clams, oysters, and mussels are done when their shells open during cooking.
How quickly do I need to refrigerate food after cooking to keep it safe?
Refrigerate cooked food within 2 hours of cooking, or within 1 hour if the surrounding air temperature is above 90°F. Use shallow containers so the food cools quickly throughout. Keeping food hot above 140°F until serving is also safe, but once it drops below that, the 2-hour clock starts.
Sources
- Cook to a Safe Minimum Internal Temperature · FoodSafety.gov (foodsafety.gov)
- Safe Minimum Internal Temperature Chart | Food Safety and Inspection Service · fsis.usda.gov
- Bacteria and Viruses · FoodSafety.gov (foodsafety.gov)
Prepared from these references and checked against them. References retrieved October 11, 2026.
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