Photo: National Food Institute, Technical University of Denmark

How to understand date labelling on food products

Tuesday 01 Apr 14


Jens Kirk Andersen

Senior Adviser
DTU Fødevareinstituttet
27 83 38 03

Food products are either labelled with shelf-life “Best before ...” or ”Use by”. It is producer’s responsibility to label food products correctly. A brief from the National Food Institute, Technical University of Denmark, explains the difference between these two labels and concludes that food quality and food safety are two different things.

If the sliced salmon in your refrigerator is labelled with a use-by date you should take this date seriously. However, there will be no problem in drinking milk labelled “Best before ...” after the date indicated, provided it has been stored correctly.

The National Food Institute concludes this in a brief to the Danish Veterinary and Food Administration prepared by Jens Kirk Andersen, senior adviser. The brief explains how to distinguish between labels with “Best before ...”, which is about food quality, and labels with “Use by ...”, which is about food safety.

”Best before …” is about quality

From the moment a food product is produced, processes take place which deteriorate flavour, smell and appearance, and the food product becomes unacceptable. This spoilage relates to the quality of the food product and need not relate to food safety. In these cases, the product should be labelled with “Best before ...”, and the consumer is then to decide whether the quality is acceptable after the date indicated.

In principle, preserved food, dried products like cereal products, pulses and spices can last endlessly, if stored under correct conditions. Under less optimal circumstances, quality may deteriorate, e.g. problems with pests, mold or bacteria growth may arise due to non-tight packaging.

”Use by …” is about food safety

Food products must be stored safely, and the storage temperature indicated must be met to avoid harmful bacteria from developing and causing diseases. When there is a risk of bacteria growth it is crucial for safety that an exact expiry date is indicated. The risk of getting ill as a result of long-time food storing is particularly seen with ready-to-eat products like cooked deli meat and smoked fish, which should be stored chilled.

Food producers ofchilled ready-to-eat products should therefore ensure that the risk of growth of disease-causing bacteria is limited to a minimum. They do this by e.g. setting an expiry date. It is producer’s responsibility to set the date, and the consumer should not exceed this date as it is actually set out of concern for food safety and consumer health.

Correct chilling reduces risk

Especially the bacterium Listeria monocytogenes is critical when deciding on correct labelling of the shelf-life. It may cause serious disease and can grow at temperatures as low as zero degrees. Therefore, this bacterium is an important reason why ready-to-eat products like e.g. soft cheeses, cooked deli meats and smoked fish are labelled with “Use by ...”.

So, consumers should not eat products when the use-by date has been exceeded. Furthermore, they should make sure that their refrigerator is sufficiently cold, corresponding to the requirements of the label. The temperature has a significant bearing on whether bacteria can grow, and consequently on the length of the period the product is eatable with no risk of causing disease.

Food may sometimes become safer during storage. Food products like parmesan-like cheese, air-dried ham and salamies are produced of raw milk and raw meat, respectively, which may contain disease-causing microorganisms. However, during storage harmful bacteria will eventually die and the food product in question becomes safe.

Read more

Read the National Food Institute’s brief to the Danish Veterinary and Food Administration: On shelf life of foods (pdf).

News and filters

Get updated on news that match your filter.