Things you need to consider when setting a shelf-life
14 July 2022
Linda Everis, Section Lead
The shelf-life of a product is the time that it remains acceptable to eat. Within the shelf-life, the product will
remain safe and retain the desired sensory, chemical, physical and microbiological characteristics.
Understanding shelf-life is essential in assuring the safety and
quality of food and drink products
It’s important to re-evaluate shelf-life when products are reformulated because changing or reducing levels of salt,
sugar or preservatives can all impact on shelf-life.
What influences shelf life?
Shelf-life is influenced by many aspects of good manufacturing practice and product formulation. Combinations of
these factors are often used together to inhibit microbial growth, and so manage microbiological shelf-life. This is known as hurdle
Raw materials introduce microorganisms and sensory attributes to the final product. Variation in the raw materials
will cause these attributes to vary in the product and may affect the shelf-life. For example, coleslaw made using freshly harvested cabbage
will have a lower count of yeasts than cold-stored cabbage and therefore will have a longer shelf-life. It’s also important to consider if
there are any in-house or external specifications you need to follow. You can find advice specifically on how to set microbiological criteria
in Campden BRI Guideline 52.
All processing exerts considerable changes on the microflora and the chemical, biochemical and sensory properties of
food. Small changes in one type of processing may have a large effect on the properties of the food and may be critical for shelf-life – for
example, in cottage cheese, small changes in pH in the range 4.5-5.5 can significantly affect the types of spoilage microorganisms that can
grow. More importantly, such changes would allow growth of pathogens should they survive the process or subsequently contaminate the product.
Intrinsic properties of the product such as pH, salt and water activity – that have been identified as critical to
product stability – must be achieved in order to ensure that all product will achieve the shelf-life that is claimed for the product.
Storage and distribution
How a product is stored during both transport and retail display will greatly affect shelf-life. Storage temperature
has the biggest effect, but light and humidity will also influence shelf-life. Customers may have different requirements for the temperature
and duration that the product will be stored at. Therefore it’s possible that one product may need to have more than one shelf-life if the
manufacturer has more than one customer.
Poor hygienic control may result in high levels of microorganisms being introduced to the product, which may have
adverse effects on its safety and quality and thus affect its shelf-life – for example, poor cleaning of meat slicing equipment will increase
microbiological counts and reduce the shelf-life of cooked meat.
Modified gas atmospheres, introduced at the time of packing or developing on storage, will influence microbial growth
and enzymatic and chemical reactions. Similarly, light, gas and packaging material permeability will influence the shelf-life.
How the consumer purchases, stores and uses the product will affect the product’s shelf-life. For example, how long
the product stays in the fridge in-store and conditions / time during transport to the consumer’s home. And once the product is taken home,
how it’s stored - for example a juice may not be returned straight to the fridge, the carton may be left on the table for periods.
The shelf-life of food products is influenced by microbiological, chemical and sensory considerations and, in some
cases, legislative requirements. Shelf-life needs to be determined by following sound scientific principles that take into account all the
relevant formulation, manufacturing, distribution and storage factors. Assigning the correct shelf-life can be the key to the commercial
success of a new product and should be done in the early stages of new product development.
Linda Everis joined Campden BRI in 1995 as a Senior Technician in the Microbiological Analytical Services group having graduated from the University
of Wales Aberystwyth with a BSc in Biology.
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How can we help you?
If you’d like to find out more about how we can help with the self-life of your products, contact
our Support Team.
This blog was first published in 25 July 2017