We know this one seems to cause a lot of confusion amongst consumers, and we often get asked by customers, so we have dragged in Shirley (our resident food safety officer) to help explain the difference.
'Use By' Dates
'Use by' is directly related to the safety of a product and is present on perishable goods. In other words, items that can spoil quickly like meat or ready-to-eat foods, such as coleslaw, pork pies, ready made salads, yoghurt, milk etc. The label is telling you that it is safe to eat that item up to and including the date, and that it is unsafe to eat when it is past it's 'use by' date. It is important to take note of 'use by' dates, as food can often be unsafe to eat even when it looks okay. Furthermore, it is actually illegal for a food business to use or sell something past it's 'use by' date.
'Best Before' Dates
'Best before' dates are related to the quality of a product. Items that have a 'best before' date on them are normally the ones that you would buy off the shelf and store in your cupboards at home. The label is telling you that the item is best consumed before it's 'best before' date, and that it safe to eat but might not be at it's best quality wise when it is passed it's 'best before' date. For instance, if you open a packet of biscuits after their 'best before' date they will not be at their freshest, but you could still eat them and they wouldn't make you ill. Furthermore, it is not illegal for businesses to sell something past it's 'best before' date as long as it has been brought to the customers attention. Shops can do this by using particular areas and different price labels for reduced items that have passed their 'best before' date.
It is also worth noting that some 'best before' items that you would buy off the shelf have particular instructions on the label, such as, once opened store in the refrigerator, or once opened use within a certain date. In these cases the labels instructions should be followed.
In short, 'use by' dates are present on perishable items. These items are unsafe to consumers after their 'use by' date, even if they look okay. 'Best before' dates indicate when a product is at it's best in terms of quality. These items are safe to consume after their 'best before' dates (as long as you follow any special instructions on the label), but their quality will have diminished somewhat.