Heat thresholds and food safety
What happens at which temperature, and at what internal temperature is food safe?
What happens at which temperature?
Each change in food starts at a specific temperature: egg white sets at 63–65 °C (145–149 °F), water boils at 100 °C (212 °F), and from about 140 °C (284 °F) the Maillard reaction browns the surface noticeably.
| °C (°F) | What happens |
|---|---|
| 5–60 (41–140) | Danger zone: bacteria multiply in this range |
| 50–55 (122–131) | Fish is moist and translucent (see the table under the next heading for the safe temperature) |
| 54–57 (129–135) | Beef is medium-rare (see the table under the next heading for the safe temperature) |
| 60+ (140+), for hours | Collagen (the protein in connective tissue) slowly turns into gelatin, so shank and ribs become tender. Higher heat shortens the time, but the meat loses more water[1][2] |
| 63–65 (145–149) | Egg white sets |
| 100 (212) | Water boils. A wet surface cannot go above this temperature. That is why a wet surface does not brown |
| About 140+ (284+) | Maillard reaction (browning between protein and sugar): the surface browns and a roasted smell forms. The reaction starts slowly at lower temperatures |
| 160–180 (320–356) | Sugar caramelizes |
| 175–190 (350–375) | Frying oil range |
At what internal temperature is food safe?
Poultry must reach 74 °C (165 °F) and ground meat must reach 71 °C (160 °F). These values are the recommendations of the US food safety agencies (USDA, FDA).
| Food | Internal temperature |
|---|---|
| Poultry | 74 °C (165 °F) |
| Ground meat | 71 °C (160 °F) |
| Whole cuts of beef and lamb | 63 °C (145 °F) + rest |
| Fish | 63 °C (145 °F) |
Room temperature: Cooked food does not stay in the 5–60 °C (41–140 °F) range for more than 2 hours.
Cooling: Food goes from 60 °C (140 °F) to 21 °C (70 °F) in 2 hours, then to 5 °C (41 °F) in the next 4 hours. The total time is 6 hours. Food divided into shallow containers cools faster.
Sources
Sources for the science numbers. A number is written as a number only when it was read in its source; anything that could not be read is written without a number.