What is the difference between "use by" and "best before" dates?

Most pre-packed foodstuffs you buy from the supermarket must carry a date of minimum durability. This can be either a "best before" date or a "use by" date. These date marks are usually on a prominent place on the label or lid.

"Best before"

This may take the form of the words "best before" followed by the date, for example "best before 1 January 2006". The date marks on longer-life food may use the phrase "best before end" followed by a date, for example "best before end May 2006".

This is the date up to and including which the food can be expected to remain at peak quality if properly stored. Food may be edible after this date; however its quality may suffer - something like potato crisps might become soft. It is not an offence under the Food Labelling Regulations to sell food passed its "best before" date.

"Use by"

This words "use by" are followed by the date, for example "use by 5 April 2005". The "use by" date is used for foods that are highly perishable and that can, after a short period, cause an immediate health risk; examples are meat pies and some ready prepared meals.

These foods could become a health risk if used after the "use by" date. Some foods, such as bread, are highly perishable but do not carry any immediate risk and are therefore labelled with a "best before" date. It is a criminal offence for your supermarket or retailer to sell, or have on display, any product that has gone beyond its "use by" date.

Eggs

There are some specific rules that only apply to eggs. Eggs must be marked with a "best before" date. This date may be up to a maximum of 28 days after the eggs are laid. Eggs must be sold to the consumer within 21 days after the eggs were laid; this means that they must be sold seven days before the "best before" date expires. Eggs marked "best before 22 March" for example, must be sold by 15 March. It is an offence to supply eggs if there are less than seven days before the "best before" date expires.

Foods that are exempt

Certain foods do not have to be marked with a "use by" or "best before" date. These include: fresh fruit and vegetables that have not been peeled or cut into pieces; wine, liqueur wine, sparkling wine and similar products; any drink with an alcoholic strength by volume of 10 per cent or more; any soft drink, fruit juice or fruit nectar or alcoholic drink sold in a container of five litres or more intended for supply to catering establishments; flour, confectionery and bread normally consumed within 24 hours of preparation; vinegar, cooking and table salt, solid sugar, flavoured or coloured sugar products, chewing gum and similar products; and individual portions of edible ices.

Trevor Tweed is a member of the Royal Institute of Public Health, an experienced catering consultant, lecturer and trainer in food safety and a campaigner for the promotion of British food producers.