Opened Ketchup Left Out Overnight: Is It Safe?
Written by Jordan Morley · Reviewed against FSA chilling & danger-zone guidance · Last updated 28 October 2026
Ketchup left out overnight is fine — its acidity and sugar make it resilient, which is why it lives on café tables. Refrigerating opened bottles simply keeps the quality best.
Why it's OK
Ketchup contains vinegar, sugar and salt, which together keep it stable at room temperature. Restaurants leave it on tables for that reason. The label asking you to refrigerate after opening is about holding colour and flavour for longer (USDA FoodKeeper gives opened ketchup around 6 months in the fridge). A night out is no problem.
You can also check the calorie content of opened ketchup alongside its safety information.
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Opened Ketchup: the other answers on this site
| Question | Short answer (links to the full page) |
|---|---|
| In the fridge (Ketchup (Opened)) | 6 months in the fridge; 1 year in the cupboard |
Common questions
Why can ketchup sit on a café table all day?
It is acidic (vinegar and tomato) and high in sugar and salt, which stop bacteria growing. A bottle on the table overnight is fine.
Does ketchup need the fridge after opening?
The label usually says so; refrigerating keeps the colour, flavour and thickness best for longer. The USDA FoodKeeper gives opened ketchup about 6 months in the fridge and about a year in the pantry.
What about the ketchup left on the plate or in a dish?
A small amount left in a dish at room temperature is fine, but don't put it back in the bottle.
How can I tell if ketchup is off?
Mould, fizzing, a sour or fermented smell, or darkening and separation beyond a bit of watery liquid.
Related answers
Primary source: FSA chilling & danger-zone guidance.
General information only, not medical advice: see the medical disclaimer. Feeling unwell after eating something? Contact NHS 111 or your GP.