British food packaging carries a great deal of information, most of it regulated, and much of it misunderstood. The single most consequential misunderstanding is the difference between a use by date and a best before date. One is a safety instruction with legal force behind it. The other is an estimate of quality made by the manufacturer. Treating them as interchangeable is how perfectly good food ends up in the bin and how occasionally unsafe food ends up on the plate.
Use by means what it says
A use by date appears on food that carries a genuine microbiological risk once it has been stored beyond a certain point: chilled meat and fish, prepared salads, dairy products, cooked meats and ready meals. The risk is that harmful bacteria can multiply to dangerous levels without any change in smell, appearance or taste, which is precisely why the date exists. You cannot inspect your way past it. Guidance from the Food Standards Agency is unambiguous on this point: food should not be eaten after its use by date, even if it looks and smells fine, and it is illegal for a retailer in the United Kingdom to sell it.
The date is also conditional on storage. A use by date assumes the food has been kept at the temperature printed on the pack, usually below five degrees Celsius. A chilled item left in a warm car for two hours has effectively had its date shortened, and no label can tell you by how much. Freezing changes the calculation entirely: food frozen before its use by date can be kept safely for months, and the date then applies from the point of defrosting rather than from the original packaging.
Best before is about quality
A best before date applies to food that will not become dangerous but will deteriorate: biscuits that soften, crisps that go stale, tinned goods whose texture dulls, dried pasta that loses nothing at all for a very long time. Passing the date is not an event. Bread a day past its best before is stale, not hazardous. Rice several months past it is entirely usable. The date is the manufacturer estimate of when the product will stop tasting the way it was designed to taste, and manufacturers have a commercial incentive to be conservative.
Eggs are the awkward case. British eggs carry a best before date rather than a use by date, and the recommendation to use them within that window relates chiefly to the risk of salmonella developing in older eggs and to the reliability of cooking methods that leave the yolk soft. Eggs from flocks in the British Lion scheme are vaccinated, which is why official advice on runny eggs for vulnerable groups was relaxed some years ago, but the storage guidance remains: keep them cool, keep them in one place and do not move them between temperatures.
What the traffic lights actually measure
The colour coded panel on the front of many British packs is voluntary rather than mandatory, and it is calculated per hundred grams or per portion. Red, amber and green refer to fat, saturated fat, sugar and salt, measured against thresholds set by government guidance. The system is useful for comparing two similar products on a shelf and much less useful for judging a food in isolation, because it takes no account of how much of the food anyone actually eats or of what else is on the plate. Olive oil scores badly on fat. A large portion of an otherwise sensible meal can score well on every axis simply because the portion declared on the pack is small.
Nutrition labelling on the back is more precise and more comparable. It must show energy, fat, saturates, carbohydrate, sugars, protein and salt per hundred grams, which makes it the only reliable basis for comparing two products of different pack sizes. Allergen information is a separate legal requirement, and the fourteen major allergens must be emphasised in the ingredients list, typically in bold. The rules covering food prepacked for direct sale, such as sandwiches made on site, were tightened in recent years so that full ingredient lists appear on those packs too.
The cost of confusion
Household food waste in the United Kingdom runs into millions of tonnes a year, and confusion over dates is consistently identified as one of the largest single contributors. Several major supermarkets have responded by removing best before dates from fresh produce altogether, on the grounds that a customer can judge an apple better than a printed date can. Consumer research published by organisations including Which? has repeatedly found that a substantial minority of shoppers discard food on the strength of a best before date alone.
A short set of practical rules
Read the label to find out which of the two dates you are looking at before you decide anything. Respect use by dates absolutely, and use the freezer to extend them rather than the calendar. Judge best before food by looking at it, smelling it and, where sensible, tasting a small amount. Keep the fridge at or below five degrees, because a fridge running warm quietly shortens every use by date inside it. Store raw meat below cooked food so that nothing drips onto anything that will not be cooked again.
None of this is complicated, but it is rarely taught. For related reading, our guide to what is in season in Britain month by month covers buying fresh food at the point when it needs the least intervention, and the Food section carries the rest of our writing on how the country shops and eats. Households looking to reduce spending more broadly may also find our guide to cutting a household energy bill useful.
Reducing what you throw away
Date labels exist partly to manage safety and partly to manage stock, and the gap between the two is where most household food waste happens. The national picture, including how much edible food UK homes discard each year and which categories dominate, is tracked by WRAP, the body that runs the Love Food Hate Waste programme. For guidance on storing and reheating food safely, particularly rice, poultry and cooked leftovers, the NHS advice on eating well sets out the practical rules in plain language. Freezing is the most underused tool: almost anything can be frozen on the use-by date rather than after it, which converts a deadline into a choice. See also our month by month guide to British seasonal produce.
