Shelf life can be a tricky thing to get right. There are many factors to consider and food producers often struggle to find the right balance between quality and longevity.
Thankfully, new solutions, or twists on old ones, regularly emerge. Let’s take a look at what shelf life is, how best to go about shelf life testing and the innovations available that might buy your product more time.
What is shelf life exactly?
Food shelf life is the length of time a product can be kept before it becomes too old to be sold or consumed. There are a few variations:
- Best before dates refer to the quality of the food rather than food safety. A product in this category can be consumed after its best before date but won’t be at its best. For example, biscuits or crisps will go soft but will still be fine to eat.
- Use by dates refer to safety, so eating a food product past these dates is risky. Foods like soft cheeses, processed deli meats and shellfish fall into this category.
- Finally, there are display until and sell by dates which are aimed at retail staff to support stock rotation. The Waste and Resources Action Programme (WRAP) advises removing these dates so as to not confuse consumers.
How to establish your new product’s shelf life
A product with a long shelf life allows plenty of time for storing, shipping and, well, sitting on a shelf ready for purchase. For new products with no existing demand, you’ll want to create as long a shelf life as possible to minimise wastage. Ideally, it should have a twelve-month ambient shelf life. However, it’s rarely practical to develop your product, store it and wait 12 months to see if it’s okay.
So what could you do instead?
- Launch with a shorter shelf life and then increase the time once you have more data
- Perform an accelerated stability test (higher temperature and/or humidity depending on the product) to give you an indication of the twelve-month shelf life within three months
- Perform microbiological challenge testing
Microbiological challenge testing simulates what happens to a product during processing, distribution, preparation and handling should it become contaminated. Selected microorganisms are inoculated to determine if they would present a potential health hazard or spoilage risk.
Five innovations for extending shelf life
Developing shelf life is an area of food technology that is constantly evolving with the development of new processes and techniques. As a result, there’s a range of options when it comes to developing the shelf life of your product.
Packaging can be more than a passive wrapping; it can be ‘active’. This means that it can respond to changes in its environment, whether those come from the food or the atmosphere around it. Active packaging includes oxygen and other gas scavengers, desiccants and antimicrobial elements. Benefit: quickly reacts to certain conditions to keep food stable.
Modified atmosphere packaging (MAP)
Also known as gas flushing, protective atmosphere packaging or reduced oxygen packaging, MAP technology pumps a package with a protective gas mix (pure oxygen, carbon dioxide and nitrogen) instead of regular, atmospheric air and can be tailored for specific products. Benefit: MAP extends shelf life without stabilisers or chemical preservatives.
High-pressure processing (HPP)
High-pressure processing is a cold pasteurisation technique subjecting packaged food to high pressure. Benefits: The process can render vegetative microorganisms inactive and the cold temperature preserves freshness (if the product remains chilled).
Microwave sterilisation process
As you might expect, the microwave sterilisation process involves heat. The product is submerged into pressurised hot water while microwaves penetrate food (at a far deeper level than conventional ovens). Benefits: sterilisation happens uniformly and quickly throughout the product reducing processing time and preserving nutrients, flavour, colour and sensory characteristics.
Light-based technology (blue LEDs, ultraviolet light and pulsed light) breaks down bacteria in food. The nature of the technology means it can’t penetrate deeply into the product, so only surface sterilisation is possible. Benefit: causes minimal impact on food quality.