Yes. Cooking kills E. coli and Salmonella when the food's internal temperature reaches the pathogen's thermal death point and holds there long enough. For poultry, that means 165°F. For ground beef, 160°F. For whole cuts of beef and pork, 145°F plus a rest. Heat denatures bacterial proteins and ruptures cell membranes, and neither species survives a properly conducted cook. The failures happen before, during, or after the heat step, not because heat is unreliable.
The Mechanism: Why Heat Is Lethal to These Bacteria
Bacterial cells are mostly water, protein, and a lipid membrane. Raising the temperature past roughly 130°F begins unfolding proteins, a process called denaturation. Enzymes lose their shape and stop catalyzing reactions. The membrane's lipid bilayer becomes fluid enough to leak. Ribosomes stall. The cell cannot repair any of this fast enough, and death follows.
E. coli and Salmonella are vegetative cells, not spore-formers. That distinction matters enormously. A vegetative cell dies when its proteins coagulate, and the temperature at which that happens is well below boiling. Bacterial endospores, produced by Clostridium and Bacillus species, survive boiling for hours because their dehydrated core and protective coats resist denaturation. E. coli and Salmonella do not build spores, so they have no such shield. The pathogen most associated with undercooked poultry is simply a fragile cell once heat arrives.
The relationship between temperature and time is logarithmic, not binary. At 145°F, Salmonella in chicken needs roughly 8.5 minutes of holding to reach a 7-log reduction, meaning a million-fold drop. At 160°F, the same reduction takes under 30 seconds. At 165°F, it is effectively instantaneous for the bacterial loads found in food. This is why the FDA's guidance targets 165°F for poultry: the target is chosen so the required hold time collapses to zero, making the rule foolproof for a cook with an instant-read thermometer.
One plain-language version: heat doesn't poison bacteria, it cooks them until their internal machinery jams, and the hotter you go, the less time that takes.
Quantified Context: What the Rules Actually Mean
The FDA Food Code sets the consumer-facing numbers, and they are not arbitrary. Poultry, including chicken and turkey, must reach 165°F internal. Ground meat, including hamburger and sausage, must reach 160°F. Whole muscle cuts of beef, pork, veal, and lamb must reach 145°F followed by a 3-minute rest. Fish follows the same 145°F rule. Egg dishes require 160°F. Reheated leftovers require 165°F.
The rest period is not a formality. Carryover cooking raises the internal temperature another 5 to 10°F after the meat leaves the heat, and the 3-minute rest at 145°F provides the time component the lethality curve requires. Cutting immediately forfeits both.
The scale of the problem is large enough to justify the precision. The CDC estimates Salmonella causes about 1.35 million infections, 26,500 hospitalizations, and 420 deaths annually in the United States. E. coli infections number in the hundreds of thousands each year, with Shiga toxin-producing strains responsible for the most severe cases. Most of these are foodborne, and the majority trace to a small set of handling and cooking failures rather than to rare events.
Temperature is the only reliable measure. Color is not. A burger can turn brown at 150°F, before it is safe, because myoglobin oxidation depends on pH and oxygen exposure, not just heat. Poultry can look pink near the bone at 165°F because bone marrow pigment diffuses into surrounding tissue. Both colors mislead in opposite directions.
Timeline: What Happens From Raw to Safe
| Time Point | Internal Temp | What Is Happening to the Bacteria |
|---|---|---|
| Raw | 40°F or below | Cells are viable, possibly multiplying slowly; cold storage stalls growth |
| 40–140°F | Danger zone | Exponential growth resumes; doubling times as short as 20 minutes near 100°F |
| ~130°F | Approaching lethality | Protein denaturation begins; cells stop dividing and start dying |
| 145°F + 3 min | Whole-cut target | Log reductions accumulate during the hold; Salmonella drops sharply |
| 160°F | Ground meat target | Lethal for E. coli O157:H7 within seconds to a minute |
| 165°F | Poultry target | Near-instant kill at the bacterial loads typical of retail poultry |
| Post-cook | Cooling through 140–40°F | Surviving cells, if any, can regrow; cooling speed matters |
The danger zone deserves emphasis. Between 40°F and 140°F, bacteria multiply, and food left in that band for more than 2 hours cumulatively is considered unsafe by FDA guidance, or 1 hour if the ambient temperature exceeds 90°F. A slow cook that spends four hours climbing from 40°F to 140°F is not a safe cook, no matter how it finishes.
Edge Cases That Break the Rule
Thickness defeats thermometers. A 3-inch-thick pork roast may read 145°F at the center while the outer layer is still at 130°F, and the geometric center of a roast is often not the coolest point. The cold spot in a whole bird is the innermost part of the thigh and the thickest part of the breast, not the cavity. The cavity is actually warmer because it is exposed to hot air.
Frozen food shifts the math. Cooking from frozen means the outer layers overcook while the core is still thawing, and the core spends extended time in the growth zone. The USDA recommends thawing in the refrigerator, in cold water changed every 30 minutes, or in the microwave, then cooking immediately.
Microwave cooking produces uneven fields. Standing waves create hot spots and cold spots within the same dish, and the cold spots may never reach lethal temperature. Stirring and a rest period help, but microwaved poultry is a genuinely higher-risk preparation than oven-roasted poultry.
Blended and mechanically tenderized meat introduces surface bacteria into the interior. Whole cuts are safe at 145°F precisely because contamination sits on the outside, where heat arrives first. Once a blade or grinder pushes that contamination inside, the entire mass must reach 160°F. This is why ground beef has a stricter standard than steak.
A counterintuitive professional caveat: a perfectly cooked burger can still make someone sick if it was handled badly after cooking. Recontamination from a cutting board, a spatula used on raw meat, or unwashed hands reintroduces live bacteria onto a sterile surface, and no further heat is coming. Cooking kills what is present at the moment of cooking. It does not sterilize the kitchen.
Misconceptions Worth Retiring
The idea that "cooking kills everything" is true in the narrow sense and dangerous in the broad one. It kills vegetative bacteria at the right temperature. It does not destroy all heat-stable toxins, and it does not undo contamination that happens afterward. Staphylococcal enterotoxin, produced when food sits in the danger zone, survives boiling. So does Bacillus cereus toxin. The bacteria that made them may be dead while the toxin remains fully active.
The color rule is a second persistent myth. USDA research found that a significant share of ground beef patties turned brown well before reaching 160°F, and a separate share stayed pink past 160°F. Visual doneness and microbiological doneness are independent variables.
The "juice runs clear" test is a third. Juice clarity reflects protein coagulation and pigment, not bacterial load, and it fails inconsistently near the target temperature.
Red-flag warnings:
Never rely on color, texture, or juice clarity as a safety endpoint for poultry or ground meat. Never reheat or "finish" food in a slow cooker that spends more than 2 hours below 140°F. Never use the same unwashed board or knife for cooked and raw meat. Never assume acid marinades, spices, or alcohol in a recipe kill bacteria; they do not. Never trust a dial oven thermometer for safety decisions; use an instant-read probe.
Comparison: Cooking Methods and Their Actual Reliability
| Method | Typical Reliability | Failure Mode | Practical Note |
|---|---|---|---|
| Probe thermometer, oven or grill | High | Probe placed in wrong spot | Measure the cold spot, not the center of a roast |
| Sous vide | Very high | Time-temperature pairing mis-set | Precision at 145–165°F is the method's strength |
| Microwave | Moderate | Cold spots from standing waves | Stir, rest, and probe before serving |
| Slow cooker | Moderate to high | Extended time in danger zone | Keep the lid on; verify 165°F before serving |
| Pan frying | Moderate | Uneven thickness, hot spots | Butterfly thick cuts or finish in oven |
| Deep frying | High | Oil temp recovery after food enters | Maintain 350°F+ and probe the thickest part |
| Smoking or low-temp barbecue | Low without probe | Long dwell below 140°F | Probe early and verify the endpoint |
The pattern is clear: reliability tracks the precision of the temperature measurement more than the sophistication of the appliance. A probe thermometer costing USD 15 outperforms a USD 800 grill used by feel.
Practical Actions: The Steps That Actually Work
Buy and use an instant-read thermometer. Calibrate it in ice water, which should read 32°F. Probe the thickest part of the meat, avoiding bone and fat, and for poultry check the thigh, the breast, and the wing joint.
Hold the endpoint. For poultry, pull at 160°F and let carryover reach 165°F, or cook to 165°F and serve. For ground beef, 160°F. For whole cuts, 145°F plus a 3-minute rest, timed from the moment the meat leaves the heat.
Probe multiple spots in large items. A 15-pound turkey has several distinct cold spots, and a single reading is not a verdict.
Cool fast. Leftovers should drop from 140°F to 40°F within 2 hours, which means shallow containers and immediate refrigeration, not a covered pot on the counter.
Separate raw and cooked. Two boards, two knives, or a wash in hot soapy water between tasks. This is the step most home cooks skip and the one that reintroduces the most risk.
Reheat leftovers to 165°F. The bacteria that grew during storage are vegetative and die at that temperature, but any toxin already produced does not.
Limitations: What Cooking Cannot Do
Cooking cannot make contaminated food sterile if the contamination arrives after the heat step. It cannot destroy preformed heat-stable toxins. It cannot fix a product that sat in the danger zone for six hours, because the bacterial load may have grown beyond what any reasonable home cook can eliminate, and the toxins may already be present.
Temperature measurement itself has limits. A probe reads one spot. A thin cut reads fast. A bone-in roast reads misleadingly cold or warm depending on proximity to bone. The FDA's 165°F rule is set so that even a poorly placed probe in a thin piece of poultry is likely to be past lethal temperature, which is part of why the poultry standard is stricter than the science strictly requires.
Finally, the evidence base is asymmetric. The relationship between temperature and time for Salmonella and E. coli is well characterized by decades of challenge studies, and the FDA's Food Code reflects that work. The relationship between temperature and time for every other hazard, including viruses, parasites, and heat-stable toxins, is not equivalently characterized. Cooking is highly reliable against the two bacteria named in the question and less reliable as a general-purpose safety intervention.
The practical conclusion is narrow and firm. E. coli and Salmonella die at temperatures a home kitchen can reach easily. The rule works when the thermometer is accurate, the probe is placed correctly, the endpoint is held, and everything that happens before and after the cook is treated as if it matters just as much as the heat.