Most household food poisoning does not come from something obviously rotten. It comes from food that looked, smelled and tasted completely normal. The bacteria that cause the majority of foodborne illness do not announce themselves — they do not necessarily produce off odours, visible slime or unusual colour. That is the central problem with the smell test, and it is why time and temperature rules exist at all.
The good news is that the rules are short, and once you know them they require almost no effort.
The danger zone
Bacteria multiply fastest in a temperature band roughly between 5°C and 60°C. Inside that range, a small population can double every twenty minutes or so under favourable conditions. Start with a handful of organisms and, after a few hours at room temperature, you can have a great many.
Everything else follows from this one idea. Refrigeration below 5°C does not kill bacteria; it slows them down dramatically. Cooking above 60°C, held long enough, does kill most of them. The zone in between is where problems accumulate.
The practical rule is the **two-hour rule**: cooked food should not sit in the danger zone for more than two hours in total, cumulatively, across its whole life. In hot weather above about 32°C, that shrinks to one hour. "Cumulatively" is the part people miss — the twenty minutes on the counter before serving, the hour on the dinner table, and the time it takes to cool before going into the fridge all add up.
How long things actually keep in the fridge
Assuming a fridge running at or below 5°C, and food that was cooled promptly:
- **Cooked meat, poultry, fish and stews** — 3 to 4 days
- **Cooked rice, pasta and grains** — 1 to 2 days at most
- **Soups and sauces** — 3 to 4 days
- **Cut fruit and salads** — 3 to 5 days, though quality fades faster
- **Opened deli meat** — 3 to 5 days
- **Hard-boiled eggs in shell** — about a week
- **Homemade dishes containing dairy or egg** — 3 to 4 days
Cooked rice deserves the shorter limit for a specific reason. *Bacillus cereus* forms spores that survive cooking. If rice is left at room temperature, those spores germinate and produce a toxin that reheating will not destroy, because the toxin itself is heat-stable. Rice left out overnight and fried the next morning is a genuine and well-documented cause of illness. Cool rice quickly, refrigerate it, and use it within a day or two.
Cooling matters more than people realise
Putting a large pot of hot stew straight into the fridge sounds cautious but works poorly. The centre of a deep container can stay in the danger zone for hours while the outside cools, and the heat load raises the temperature of everything else in the fridge.
Better approaches:
- Divide into shallow containers no more than about 5cm deep
- Leave the lid off or ajar until the food is no longer steaming, then seal
- For large batches, sit the pot in a sink of cold water and stir occasionally
- Aim to get food from cooked to refrigerated within two hours
Modern fridges handle warm food far better than older ones, so the folk rule about never putting anything warm in the fridge has largely been superseded. Getting food out of the danger zone quickly is the higher priority.
Reheating
Reheat until steaming hot throughout — the usual target is 74°C at the centre. Stir partway through if using a microwave, because microwaves heat unevenly and cold pockets are exactly where surviving bacteria sit.
Reheat only the portion you intend to eat. Every cycle of cooling and reheating sends food through the danger zone again, and repeatedly reheating the same batch is both a safety and a quality problem. As a general guide, reheat any given portion once.
The freezer
Freezing at or below −18°C effectively stops bacterial growth. It does not sterilise — organisms resume activity on thawing — but it stops the clock.
Frozen food therefore stays safe more or less indefinitely. The dates you see quoted are quality limits, the point at which texture, flavour and moisture begin to suffer from ice crystal damage and freezer burn:
- Cooked dishes and stews — 2 to 3 months
- Raw mince — 3 to 4 months
- Raw steaks, chops and joints — 6 to 12 months
- Poultry pieces — around 9 months
- Bread — around 3 months
Thaw in the fridge, in cold water changed every half hour, or in the microwave immediately before cooking. Thawing on the counter leaves the outer surface sitting in the danger zone for hours while the middle is still frozen.
Best before versus use by
These two phrases mean genuinely different things, and conflating them causes an enormous amount of unnecessary waste.
**Best before** is a quality date set by the manufacturer. Past it, biscuits go soft and tinned tomatoes lose brightness, but the food is not unsafe. Dried pasta, rice, tinned goods, honey and spices remain perfectly usable well beyond it.
**Use by** is a safety date, and it appears on foods that support rapid bacterial growth — fresh meat, fish, ready meals, some dairy. This one is worth respecting, because the food can become unsafe before it shows any sign of spoilage.
Where the smell test does and does not work
Spoilage bacteria — the ones that cause sourness, sliminess and off smells — are usually different organisms from the pathogens that make you ill. Food can be heavily contaminated with the second group while the first has barely started.
So the smell test is a reasonable guide to whether milk has soured or fish has gone off. It is not a reliable guide to whether four-day-old chicken is safe. Where they disagree, trust the calendar.
A short list worth being strict about
- **Rice and cooked grains** — the *B. cereus* problem is real
- **Reheated cooked chicken** — heat it thoroughly, not just warm
- **Anything containing raw or lightly cooked egg** — homemade mayonnaise, mousse, tiramisu
- **Soft cheeses and unpasteurised dairy** — especially during pregnancy
- **Shellfish** — narrow safety margins and fast deterioration
- **Food for anyone vulnerable** — young children, older adults, pregnant people and anyone immunocompromised deserve tighter margins
Summary
Keep food out of the 5–60°C zone, counting the whole cumulative time. Most cooked leftovers are good for three to four days refrigerated; rice and cooked grains only one to two. Cool in shallow containers within two hours, reheat each portion once until steaming, and treat use-by dates as rules while treating best-before dates as suggestions. When the calendar and your nose disagree, the calendar is the better witness.
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