The use-by-date gives consumers an indication of the length of time a food can be kept without a significant loss of the food's initial quality. This is a subjective judgement but it is unlikely to be in the best interest of a food producer to recommend a time which results
in a noticeable deterioration in taste, flavour or appearance of the product. Obviously, the quality
or freshness of a food when it is eaten will reflect both the length of time and conditions under
which it was stored as well as its original quality.
The use-by-date is valid only if any storage instructions included on the label are followed. For example, frozen foods generally have a long life provided they are maintained in a deep freezer at -18°C. If they are kept in a refrigerator at -4°C, or allowed to thaw in the car on the way home, the use by-date is no longer valid and the time before quality noticeably deteriorates is considerably reduced. Refreezing will not extend the life of the product to its original date. For some foods, no particular storage conditions are necessary and the food will maintain its quality under most conditions. Foods can generally be expected to maintain good to fair quality some time past the use-by-date, particularly in the case of longer life foods such as frozen and canned products. The date usually includes a margin before it has deteriorated to a stage where it becomes unsafe to eat. For maximum enjoyment, nutrition and safety, foods should be stored under the conditions specified on the label and eaten before the use-by-date has expired.