General Knowledge

Use by, best before, and the difference that matters

Use by is a safety date and best before is a quality date. Confusing the two wastes food and occasionally causes real risk. Here is the difference.

By Updated 5 min read
A printed date label on food packaging.
Photo: Chenspec, via Wikimedia Commons (CC BY-SA 4.0).

Key takeaways

  • Use by is about safety; best before is about quality.
  • Do not judge use-by foods by smell or appearance.
  • Many best-before foods are fine well beyond the date.
  • Freezing before the use-by date pauses the clock; thawed food should be used promptly.

Two labels on food packaging look like they mean the same thing and do not. One is about safety and one is about quality, and confusing them costs households a substantial amount of money in food thrown away while it was still perfectly good, and occasionally causes someone to eat something they should not have.

The distinction is worth learning once, properly.

Use by is about safety

A use-by date is the manufacturer’s assessment of the point beyond which the food may not be safe to eat, even if it has been stored correctly and looks and smells fine. It appears on foods where harmful bacteria can multiply without producing any obvious sign: fresh meat and poultry, fish, ready meals, prepared salads, soft cheeses, and most fresh dairy.

This is the important part. The bacteria that cause food poisoning, including listeria and salmonella, do not necessarily change the smell, appearance or taste of food. The sniff test, which is a reasonable instrument for many things, does not detect them. That is precisely why use-by dates exist.

Do not eat food after its use-by date. Do not judge it by eye. In the UK it is also illegal for a retailer to sell food past that date.

Best before is about quality

A best-before date, sometimes printed as best before end, is about the food being at its best: texture, flavour, colour, crispness. Past it, the product is generally still safe. It may simply be less good.

It appears on foods where the safety risk is low: dried pasta, rice, tinned goods, biscuits, crisps, flour, sugar, frozen food, and most long-life products. A tin of tomatoes two years past its best-before date is very unlikely to be dangerous. It may have softened and lost some flavour.

This is where most avoidable waste happens. Households throw away sealed, unspoiled dry goods because a date has passed that was never a safety date in the first place.

Use by against best before, and what each one is telling youA use-by date is a safety date. It appears on fresh meat, fish, ready meals, prepared salads, soft cheese and fresh dairy, where harmful bacteria can multiply without changing the smell or appearance. Do not eat past it and do not judge by eye. A best-before date is a quality date. It appears on dried pasta, rice, tins, biscuits, flour, sugar and frozen food, where the safety risk is low, and past it the food is generally still safe but may be less good. Below, the labels that are not dates at all, and the four best-before exceptions worth respecting.USE BYThis is a safety date.Fresh meat and poultry, fish, readymeals, prepared salads, soft cheese,most fresh dairy.Harmful bacteria need not change thesmell, look or taste at all.Do not eat past it. Do not sniff it.BEST BEFOREThis is a quality date.Dried pasta, rice, tinned goods,biscuits, crisps, flour, sugar,frozen and long-life products.Past it the food is generally still safe.It may simply be less good.This is where most waste happens.Not dates for you at allSell by / display until — stock rotation for the shop.Freeze by — the last day it can go in the freezer.Once opened, use within X days — this overrides the printed date entirely.The most commonly missed instruction on any package.Best-before exceptionsEggs — the 28-day date is set with salmonella in mind.Oils and nuts — these go rancid rather than mouldy.Damaged tins — dented, swollen or leaking: discard.Baby formula — never use past the date.Every date assumes correct storage. The label is only as good as the fridge.
The distinction is worth learning once: one of these two labels is about whether food will hurt you and the other is about whether it will be nice. Confusing them costs money in one direction and carries real risk in the other. Diagram by HRITU.

The other labels

  • Sell by / display until. Stock rotation instructions for the shop, not for you. They are increasingly being removed from packaging for exactly that reason.
  • Freeze by. The date up to which the food can be frozen and still be good after thawing.
  • Once opened, use within X days. This overrides the printed date entirely. An unopened carton good for another fortnight may be good for three days once opened, because opening it introduces contamination and interrupts the sterile packaging.

That last one is the most commonly missed instruction on any package.

Freezing resets the clock, within limits

Food can be frozen right up to the end of its use-by date, and freezing effectively stops the clock. Once thawed, treat it as fresh: eat it within about 24 hours and do not refreeze it raw. Guidance in both the UK and US now accepts that home freezing at any point before the use-by date is fine, replacing older advice to freeze on the day of purchase.

When a best-before date should still be respected

The generalisation that best-before dates are safe to ignore has real exceptions.

  • Eggs. In the UK the date on eggs is a best-before, set at 28 days, but it is set with salmonella risk in mind. It is not worth stretching, particularly for anything served raw or lightly cooked.
  • Oils and nuts. These go rancid rather than mouldy. Rancidity is a quality problem rather than an acute safety one, but the taste is unpleasant and the fats have degraded.
  • Anything with visible damage. A dented, swollen, rusted or leaking tin should be discarded regardless of date. A swollen tin in particular can indicate bacterial growth.
  • Baby formula. Never use past its date. Nutrient content is guaranteed only to that point.

Storing so the dates mean what they say

Every printed date assumes correct storage, so the label is only as good as the fridge.

  • Keep the fridge at or below 5 °C, and check it with a thermometer rather than trusting an unmarked dial.
  • Raw meat on the bottom shelf, always, so nothing can drip onto food below it.
  • Do not overfill the fridge to the point where air cannot circulate, which creates warm pockets.
  • Refrigerate leftovers within about two hours and eat them within two days.

For the appliance all of this depends on, see how a refrigerator actually works, and for why the fridge is the wrong place for one particular item, why bread goes stale faster in the fridge.

Sources

  1. UK Food Standards Agency, best before and use-by dates
  2. WRAP, research on household food waste and date labelling

Frequently asked questions

Depends which date it carries. Most yoghurt in the UK now has a best-before date, and unopened pots are typically fine for a week or two beyond it if refrigerated properly. If yours carries a use-by date, respect it. Discard any pot with mould, a swollen lid or an off smell regardless.

Not useless, but limited. It is good at detecting the spoilage organisms that make food unpleasant, and unreliable at detecting the pathogens that make food dangerous. Use it as a reason to throw something out, never as a reason to keep something past a use-by date.

A great deal. UK studies by the waste organisation WRAP have repeatedly found that a large share of avoidable household food waste is thrown out because of date labels, and several retailers have removed best-before dates from fresh produce specifically to address it.

HRITU Editorial Desk is the byline for pieces produced in-house by the HRITU editorial team. We write about cooking, travel, science and everyday knowledge, and we explain the reasoning behind what we publish rather than just stating conclusions. Every article is checked against primary or reference sources before it goes out, dated on publication, and updated in the open when we learn something is wrong. Corrections and questions are welcome at info@hritu.com.

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