These two labels look similar, sit in the same place on the packet, and mean entirely different things. One is a safety instruction with legal force. The other is the manufacturer's opinion about when the product stops being at its best.
Treating them the same in either direction causes a problem. Ignoring a use by date is a genuine food safety risk. Binning food on its best before date is how a significant amount of perfectly good food ends up in the bin.
The Short Answer
USE BY is about safety. It appears on foods that spoil in ways you may not be able to see, smell or taste — fresh meat, fish, dairy, ready meals, prepared salads. Food should not be eaten after its use by date, even if it looks and smells fine. That's the point: harmful bacteria don't necessarily announce themselves.
BEST BEFORE is about quality. It appears on foods that don't carry the same bacterial risk — tinned goods, dried pasta, rice, biscuits, crisps, frozen food. After that date the food may be less good than it was. It is not automatically unsafe.
The freezing rule: you can freeze food right up to the end of the use by date. Freezing stops the clock. Once thawed, use it within 24 hours and don't refreeze it raw.
Once opened, the date on the packet may no longer apply. An "once opened, use within 3 days" instruction overrides the printed date if it falls sooner.
Eggs are the odd one out — they carry a best before date, and the advice is to use them by it rather than long after.
What Actually Matters
The two labels reflect two different kinds of deterioration. Use by covers microbiological risk: bacteria multiplying to levels that make food unsafe. Best before covers quality: staleness, texture, flavour, colour. Different mechanisms, different consequences.
You cannot detect the difference by inspection. This is the crux. Food past its use by date can look, smell and taste completely normal while carrying a bacterial load that will make you ill. The reason the label exists is precisely that your senses aren't a reliable guide.
Conversely, for best before foods, your senses are a reasonable guide. Dried pasta a year past its date is fine. Biscuits are soft rather than dangerous.
Storage conditions are assumed. Both dates assume the food has been kept as instructed. A use by date on chilled food assumes it's been at or below 5°C throughout. A fridge running at 8°C invalidates the assumption, which is a reason to know what your fridge is actually doing.
Detailed Analysis
What legally has to carry which
Under UK food labelling rules, prepacked food must carry either a use by or a best before date, and which one depends on the product.
Use by is required on food that is highly perishable and likely to present an immediate danger to health after a short period. In practice: fresh meat and poultry, fish, dairy, prepared salads, sandwiches, ready meals, and cooked meats.
Best before is used for everything else. Tinned and dried goods, frozen food, ambient bakery, confectionery, and most store cupboard items.
Some foods need no date at all — fresh fruit and vegetables that haven't been peeled or cut, wine and drinks over 10% alcohol, vinegar, salt, and sugar among others.
It is an offence to sell food past its use by date. It is not an offence to sell food past its best before date, provided it's still fit to eat, which is why you see reduced-price sections and surplus food outlets doing exactly that.
Foods where use by really matters
Not all use by dates carry the same weight, and it's worth knowing where the risk concentrates.
Ready-to-eat foods are the highest concern, because there's no cooking step to kill anything that has grown. Cooked meats, sandwiches, prepared salads, smoked fish and soft cheeses fall here. Listeria is the organism of particular concern, since it can grow slowly even at fridge temperatures.
Raw meat and poultry matter, but a thorough cooking step provides protection that ready-to-eat foods don't have. That is not a licence to ignore the date — spoilage bacteria will have been at work and some toxins survive cooking.
Dairy varies. Pasteurised milk that has soured is unpleasant rather than acutely dangerous and announces itself clearly. Soft cheeses are a genuine listeria concern.
Anyone pregnant, elderly, very young or immunocompromised should treat use by dates strictly. The margins that a healthy adult might get away with are not the same margins for those groups.
Best before, and using judgement
Here your senses are a legitimate tool, and the following are generally fine well past the date if stored properly and undamaged.
- Tinned food — often years. Reject any tin that is bulging, badly dented at a seam, rusted through, or that hisses when opened.
- Dried pasta and rice — very long. Quality declines slowly.
- Frozen food — safe indefinitely at -18°C. Quality declines, which is what the date refers to.
- Biscuits, crisps, cereal — go stale rather than dangerous.
- Honey, sugar, salt, vinegar — essentially indefinite.
- Flour — the exception worth watching. Fats in wholemeal flour go rancid, and it can develop weevils.
Things to be more careful about even with a best before: anything containing nuts or oils, which go rancid; and anything where the packaging integrity has failed, since the date assumes the seal held.
Freezing as a way to stop the clock
The most practically useful thing in this whole area, and it's underused.
You can freeze food at any point up to the end of the use by date, and freezing effectively halts bacterial growth. A pack of chicken on its use by date that goes into the freezer that day is fine.
Once frozen and then thawed, treat it as fresh: use within 24 hours, keep it refrigerated while thawing, and cook it thoroughly. Don't refreeze raw food that has thawed — although you can freeze it again once it has been cooked, which is a distinction people find confusing but which is genuinely how it works.
Freezing on the day of purchase rather than on the use by date gives better quality, since you're freezing food that's fresher. The date is the limit, not the target.
Real-World Considerations
Fridge temperature underpins every chilled use by date, and a lot of domestic fridges don't meet it. UK guidance is 5°C or below. Fridges commonly run warmer, particularly in the door and in warm kitchens. If your fridge is at 8°C, the use by dates on everything in it are optimistic.
Date labelling has been changing. Several supermarkets have removed best before dates from fresh fruit and vegetables entirely, on the reasonable basis that people can see whether a carrot is fit to eat. Some have moved milk from use by to best before, since sourness is obvious. Expect more of this.
"Display until" and "sell by" are shop stock-control marks, not consumer instructions. They have no legal meaning for you and can be ignored.
Once-opened instructions override printed dates when they're shorter. A jar with a best before of next year that says "refrigerate after opening and use within 4 weeks" is governed by the four weeks.
And the scale of the waste is worth stating. British households throw away a substantial quantity of edible food every year, and date confusion is a recognised contributor. Understanding which label is which is one of the few genuinely free ways to reduce a food bill.
Common Mistakes Buyers Make
- Binning food on its best before date. It's a quality marker. Tinned and dried goods are usually fine well past it.
- Eating food past its use by because it smells fine. The label exists precisely because your senses aren't reliable for this.
- Not freezing on the use by date. Freezing stops the clock and it's allowed right up to the end of the date.
- Ignoring once-opened instructions. They override the printed date when shorter.
- Treating "display until" as a consumer date. It's a shop stock mark with no meaning for you.
- Assuming the fridge is cold enough. Chilled use by dates assume 5°C or below and many fridges run warmer.
- Refreezing thawed raw meat. Cook it first, then it can be frozen again.
- Applying the same judgement to everyone. Pregnancy, age and compromised immunity all narrow the margins considerably.
Alternatives Worth Considering
A fridge thermometer is the practical companion to all of this. Every chilled use by date assumes 5°C or below, and knowing whether yours achieves that is a few pounds and one day's measurement.
A use-first shelf in the fridge, checked before shopping, addresses the actual cause of most date-related waste — which is forgetting things exist rather than misreading labels.
Freezing in portions on the day of purchase rather than at the last minute gives better quality and removes the deadline entirely. Meat frozen flat in portions also thaws in an hour rather than a day.
And for reducing waste more broadly, surplus food apps and reduced sections exist precisely because best before is a quality date and food past it is still legal to sell. Buying that way is cheap and entirely reasonable for store cupboard items.
Frequently Asked Questions
Can you eat food after the best before date?
Usually yes. Best before is about quality rather than safety, and tinned, dried and frozen goods are commonly fine well past it.
Is use by a legal date?
It's a safety date and it's an offence to sell food past it. Food should not be eaten after its use by date even if it seems fine.
Can you freeze food on its use by date?
Yes. Freezing stops bacterial growth, and you can freeze right up to the end of the date. Use within 24 hours once thawed.
What does 'display until' mean?
It's a shop stock-control mark with no legal meaning for consumers. Ignore it.
Do eggs have a use by date?
Eggs carry a best before date, and the advice is to use them by it rather than well beyond.
Can you refreeze food after thawing?
Not raw. You can cook thawed food and then freeze the cooked dish, which is a different thing.
Final Thoughts
The distinction is genuinely simple once it's clear: use by is a safety limit you shouldn't cross, best before is an opinion about quality that you can reasonably judge for yourself.
The habit worth building is freezing rather than binning. Anything approaching its use by date that you're not going to eat can go in the freezer that day, and the deadline disappears. It's the single most effective response to a date label, and it works on almost everything.
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