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Fermentation and preservation · beginner

Food-safety temperatures

Bacteria multiply fastest between 5 and 60 °C, so cook food hot enough, keep it out of that range and cool leftovers quickly.

What happens

Most food-poisoning bacteria grow fastest at warm temperatures between about 5 and 60 °C, the 'danger zone', and can double every 20–30 minutes in ideal conditions. Cold slows or stops growth but doesn't kill bacteria; freezing pauses them. Cooking kills bacteria through a combination of temperature and time: higher temperatures work in seconds, slightly lower ones need longer. Some bacteria, such as Bacillus cereus in rice and Clostridium perfringens in large pots of stew, form heat-resistant spores that survive cooking and grow again if food cools slowly; B. cereus can also make a toxin that reheating doesn't destroy. So safe handling is about cooking well, then cooling and storing quickly and correctly.

Why it matters in the kitchen

A thermometer and a few rules prevent most home food poisoning, especially with poultry, minced meat, rice, eggs and leftovers.

Temperatures and conditions

  • Freezer up to -18 °C
  • Fridge 0–5 °C · UK FSA advises 5 °C or below; USDA advises 4 °C or below.
  • Danger zone 5–60 °C · Limit time here; refrigerate cooked food within 2 hours, sooner in hot weather.
  • Hot holding from 63 °C · Keep hot food at 63 °C or above (UK legal minimum).
  • Whole cuts of beef, pork, lamb; fish from 63 °C · USDA, with a 3-minute rest for meat. Mince must reach 71 °C.
  • Minced meat and egg dishes from 71 °C
  • Poultry, stuffing, reheated leftovers from 74 °C · UK FSA alternatively advises 70 °C for 2 minutes in the centre.

In practice

  • Checking a chicken thigh near the bone reaches 74 °C.
  • Spreading cooked rice on a tray to cool and refrigerating it within an hour.
  • Dividing a large pot of dal or curry into shallow containers to cool quickly.
  • Thawing frozen meat in the fridge, not on the kitchen counter.

Myths and facts

  • Myth: Let food cool completely on the counter before refrigerating, or it will spoil the fridge.

    Fact: Leaving food out for hours keeps it in the danger zone. Cool it quickly in shallow containers and refrigerate within about 2 hours (within 1 hour for rice); modern fridges cope with warm food.

  • Myth: Washing raw chicken removes bacteria.

    Fact: Rinsing splashes bacteria onto the sink, worktop and nearby food. Cooking to 74 °C kills them; skip the rinse.

  • Myth: If it smells and looks fine, it's safe.

    Fact: Food-poisoning bacteria usually don't change smell, taste or appearance. Time and temperature, not your nose, decide safety.

  • Myth: Reheating thoroughly makes any leftovers safe.

    Fact: Some bacteria, like Bacillus cereus in rice, produce toxins that survive reheating. Cooling quickly and storing properly matters more than reheating hot.

  • Myth: Freezing kills bacteria.

    Fact: Freezing stops growth but most bacteria survive and become active again when thawed.

Use it to cook better

  • Use a probe thermometer in the thickest part, away from bone.
  • Cool cooked rice within 1 hour, refrigerate, eat within 24 hours and reheat only once until steaming hot.
  • Keep garlic, ginger or herbs in oil in the fridge and use within about 4 days, or freeze.
  • Refrigerate leftovers within 2 hours (1 hour in very hot weather) and eat within 2–3 days.
  • Thaw in the fridge, or in cold water changed every 30 minutes, or in a microwave if cooking immediately.
  • Keep raw meat on the bottom shelf and use separate boards for raw meat and ready-to-eat foods.
Going deeper

Pathogen kill is described by time-temperature tables: for example, poultry is considered safe almost instantly at 74 °C, or after holding at lower temperatures for longer (as used in sous vide), because bacteria die at a rate that rises steeply with temperature. Spore-forming bacteria are controlled by cooling quickly through the range where spores germinate and grow (about 50 °C down to 5 °C), which is why guidance focuses on rapid cooling of rice, stews and stocks.

Ingredients it affects most

Techniques that rely on it

Worth double-checking

  • Thresholds differ slightly between agencies: USDA uses 4–60 °C (40–140 °F) for the danger zone; the UK FSA uses 8–63 °C legally and recommends fridges at 5 °C or below.
  • Rice guidance (cool within 1 hour, eat within 24 hours) is UK FSA/NHS advice.
  • Leftover storage times vary by food and agency.

See it in recipes