Two marks, two questions
Food information law in Great Britain requires a prepacked food to carry either a date of minimum durability, expressed as a best before date, or a use by date. Which one applies is not a matter of preference. Foods that are highly perishable from a microbiological point of view, and which therefore present an immediate danger to human health after a short period, must carry a use by date.
That distinction sets up everything else. A use by date exists because you cannot reliably detect the hazard yourself. A best before date exists because quality declines, and the manufacturer is telling you when it expects that decline to become noticeable.
The Food Standards Agency puts the practical version of this plainly: use by is about safety, best before is about quality. That is a much more useful mental model than treating the two as a scale of urgency.
What a use by date actually constrains
Three things follow from a use by date, and they are worth separating.
It binds the seller. Selling food after its use by date is an offence. This is why retailers remove stock, why reduction stickers appear as the date approaches, and why a date-expired item on a shelf is a compliance failure rather than a bargain.
It is conditional on the storage instruction. A use by date is valid only if the food has been kept as the label directs. A chilled product that has spent an afternoon out of the fridge has not had its use by date extended by the fact that the printed date has not yet passed. The date and the storage line are a single instruction split across two lines of type.
It is not a sensory test. The whole reason for the mark is that the relevant hazards do not announce themselves through smell, appearance or taste. Food past its use by date should not be eaten even where it looks and smells normal, which is the FSA position and the reason the mark exists at all.
Freezing changes the position, because it halts microbiological growth. Guidance from the FSA covers freezing food up to the use by date and the handling that follows. The detail matters and belongs to the FSA rather than to a summary.
What a best before date is claiming
A best before date is a manufacturer's statement about quality: texture, flavour, colour, aroma, and in some cases the performance of a functional ingredient. It is set through shelf life testing and it carries a margin, because the manufacturer is protecting a reputation rather than the last possible day of acceptability.
Food may legally be sold after its best before date, provided it is still of the nature, substance and quality demanded and is not unsafe. Some retailers do this, and where they do, the price is usually reduced and the position is disclosed. That is a lawful trade, not an evasion.
The judgement about eating food past a best before date is a sensory one for many ambient products, and it is one the shopper is being invited to make. The absence of a legal prohibition is not permission from anyone in particular. It is simply the recognition that quality decline is gradual and not a safety event.
| Use by | Best before | |
|---|---|---|
| What it is about | Safety | Quality |
| Applies to | Foods that are highly perishable microbiologically | Foods where deterioration is a quality matter |
| Can a shop sell after it | No, selling after the date is an offence | Yes, if the food is still fit and properly described |
| Depends on storage | Yes, entirely | Yes, for the quality claim |
| Can you judge by smell or appearance | No, that is why the mark exists | Often, and that is the judgement being invited |
| Overridden by an opened instruction | Yes | Yes |
Structure set out by this newsroom from the published rules named in the sources below. It is not a survey, a measurement or a market study.
Which foods get which mark
The rule points at microbiological risk, not at how fresh a food feels. That produces some placements which surprise people.
Certain foods are exempt from date marking altogether under the food information rules, including some where deterioration is not the relevant concern. Others carry a best before despite being perishable in the everyday sense, because the deterioration path is quality rather than an immediate hazard.
Where a product is sold loose rather than prepacked, the date marking obligations are different again, and the relevant information may be displayed at the point of sale rather than on the item. That is a different part of the rules and a different set of duties for the business.
Date labels and the waste argument
Date marking sits inside a live policy debate about household food waste, and it is worth describing the debate accurately rather than taking a side in it.
The core of the argument is that best before dates on products with no safety dimension can cause food to be discarded while it is still good, because shoppers read any printed date as an instruction. Guidance in this area, including work published by WRAP, addresses how businesses choose between marks, how storage advice is worded and where a date mark can be removed altogether without creating a safety issue.
The counter-consideration is that removing dates removes information, and that a date mark is also a stock rotation instrument for retailers and a quality guarantee for manufacturers. Businesses changing their practice here are making a judgement inside a framework, not overriding it.
The one thing that is not in dispute is that the argument concerns best before dates. Nobody proposes relaxing use by dates, because those exist for a reason that is not about quality at all.
Reading the date line properly
Three details on the date line are easy to miss and change the meaning.
The date is printed with the words. A number on its own is not a date mark. The words use by or best before are part of the mark, and looking for them first prevents the most common misreading of all.
Best before end. Where durability is longer, the date can be expressed as a month and year, or a year alone, in which case the wording becomes best before end. The precision of the date is itself information about the expected shelf life.
Once opened. A separate instruction frequently appears near the date, telling you a period within which to consume the food after opening. This overrides the printed date. A product with a long best before date and a short once-opened instruction is two different shelf lives in one pack.
Where this stops
Everything here describes what the marks mean and who they bind. It is not advice about whether a particular item in your fridge is safe. Food safety in the home depends on storage, handling, temperature and the specific food, and the Food Standards Agency and Food Standards Scotland publish guidance written for exactly that purpose. If you are unwell, or if the question concerns someone at higher risk, the NHS is the right starting point rather than any publication.
Elsewhere on Feedworthy. How the ASA decides a food advert is misleading. Artisan, farmhouse, handmade: the words with nothing behind them. Free range, grass fed, outdoor bred: which are defined and by whom.