Household food waste is a large number in every country that measures it, and a meaningful share of it is food thrown away because of a date on the packet.
The dates mean different things, the difference is important, and surveys consistently find that a large proportion of people don't know which is which.
The two labels
Use by is a safety date. It appears on foods where consumption after the date carries genuine microbiological risk — fresh meat, fish, ready meals, some dairy. The date reflects testing on how long the product remains safe under specified storage conditions.
Food past its use-by date should not be eaten, even if it looks and smells fine. Some pathogens produce no sensory signs at all, which is precisely why the date exists.
Best before is a quality date. It indicates the period during which the product is at its best — texture, flavour, appearance. After it, the food is generally still safe; it may just be less good.
Dried pasta, rice, tinned goods, biscuits, most preserves. These carry best-before dates and remain edible long past them, sometimes by a very long margin.
Which foods have which
The allocation is largely determined by regulation and by the microbiological characteristics of the food.
Products supporting the growth of harmful bacteria get use-by dates. Products that don't — because they're dry, high in sugar or salt, acidic, or sterilised and sealed — get best-before dates.
Which is why a tin of tomatoes carries a best-before date measured in years while a fresh chicken breast carries a use-by date measured in days.
Eggs, the awkward case
Eggs generate the most confusion because the labelling differs between jurisdictions and the underlying risk is genuinely intermediate.
In some places eggs carry a best-before date, in others a use-by. Either way, the practical guidance is that eggs stored properly are usually fine for some time after, with the caveat that vulnerable groups — pregnant women, young children, elderly people, anyone immunocompromised — should be more cautious and should avoid raw or lightly cooked eggs entirely unless they carry a recognised safety mark.
The float test — a fresh egg sinks, an old one floats due to gas accumulation — is a reasonable freshness indicator and is not a safety test. An egg that sinks can still be contaminated.
Storage is what the dates assume
An underappreciated point: every date assumes specified storage conditions, usually stated on the packet.
A use-by date on chilled food assumes refrigeration at or below a specified temperature, typically around five degrees. Domestic fridges are frequently warmer than that, and many people have never checked.
A fridge running at eight or nine degrees will not deliver the shelf life the date assumes. A cheap fridge thermometer is one of the more useful things you can own and almost nobody has one.
Similarly, once opened, the date on the packet is superseded by whatever the opened-product guidance says — usually a much shorter period.
Freezing changes the calculation
Freezing effectively stops the clock. Food frozen before its use-by date can be kept for months and used later.
The common belief that you can only freeze food on the day of purchase is not correct — you can freeze it any time up to the use-by date. Quality degrades slowly in the freezer, safety does not, provided the food was safe when frozen and is handled properly on thawing.
The important rules are: freeze before the date, thaw in the fridge rather than at room temperature, use within a day of thawing, and don't refreeze thawed raw food unless it's been cooked in between.
What actually causes waste
Beyond confusion about labels, a few patterns show up repeatedly in the research on household waste.
Buying more than needed, especially on multi-buy offers. Poor visibility — food at the back of a fridge that's forgotten until it's past use. Cooking more than gets eaten. And a general tendency to over-cater, which is culturally reinforced and hard to shift.
The interventions with the best evidence are unglamorous: meal planning, a shopping list, and organising storage so older items are visible and used first.
The reasonable position
Respect use-by dates absolutely. They exist because the alternative is people getting seriously ill, and the sensory check is unreliable for exactly the organisms that matter.
Treat best-before dates as guidance about quality and use your judgement. Dried and tinned goods well past their date are almost always fine. Look, smell, and if it's genuinely off you'll know.
And check your fridge temperature. It's the single most consequential thing on this list and it takes one evening to sort out.
The date-free direction
Several retailers have begun removing best-before dates from fresh produce entirely, on the reasoning that fruit and vegetables are assessed perfectly well by looking at them and that a printed date prompts people to discard edible food.
The early evidence on this is encouraging, and it is a rare intervention where the retailer, the customer and the environment all benefit.
The obvious limit is that it only works where the sensory check is reliable. Nobody is proposing removing use-by dates from chicken, and nobody should. The distinction being drawn is exactly the one this piece is about, which suggests the labelling system could have been clearer from the start.