You determine the shelf life of a food by storing representative samples under realistic conditions and testing them at intervals until they fail on safety, quality or sensory grounds. The declared date is then set before that failure point, with a margin, and verified over time.
Shelf life is not a number copied from a competitor or a supplier's sales sheet. It is a food safety decision that must be supported by evidence, because a date that is too long can put a pathogen such as Listeria monocytogenes on a consumer's plate.
Auditors and inspectors ask to see that evidence. A business that cannot show how it set its dates is exposed during audits, customer approvals and recalls.
Use-by vs best-before
Use-by dates are about safety. They are used for highly perishable foods, such as chilled ready-to-eat products, where the food could become unsafe after the date even if it looks and smells normal.
Best-before dates are about quality. After the date, the food may lose flavour, texture or colour but is not expected to become unsafe if stored as instructed. Typical examples are biscuits, dry pasta and canned foods.
Terminology varies: some codes use expiry date, and some require both production and expiry dates.
What controls shelf life
Change any of these factors and the shelf life must be re-evaluated.
- Intrinsic factors: pH, water activity, salt and sugar content, preservatives, natural antimicrobials, the initial microbial load and the product's structure.
- Extrinsic factors: storage temperature, packaging material, modified atmosphere packaging (MAP) or vacuum packing, light, oxygen exposure and handling through distribution, retail and the consumer's home.
Packaging deserves care. MAP and vacuum packing slow spoilage organisms, but they can create conditions for anaerobes. UK Food Standards Agency guidance, for example, limits chilled vacuum-packed and MAP foods to 10 days unless specific controlling factors for non-proteolytic Clostridium botulinum are in place.
Types of shelf-life study
| Study type | What it answers | When to use | Limitations |
|---|---|---|---|
| Real-time storage study | How the product changes under intended storage until it fails | Every new or reformulated product | Slow; reflects only the conditions tested |
| Accelerated shelf-life testing | How fast quality or chemical deterioration happens at raised temperature | Ambient, shelf-stable foods (rancidity, browning, texture) | Limited value for microbiological safety of chilled foods |
| Durability study | Whether naturally present organisms grow during shelf life | Ready-to-eat foods, especially for Listeria | Natural contamination may be low or absent in samples |
| Challenge test | Whether a pathogen can grow in the product if present | Ready-to-eat foods where growth potential is uncertain | Needs a competent lab; specific to the recipe tested |
| Predictive microbiology model | Expected growth under given pH, water activity and temperature | Screening recipes and supporting other studies | Model only; must be confirmed with product data |
Challenge tests and durability studies
A challenge test deliberately inoculates the product with the target organism, then measures growth during storage. A durability study tests naturally contaminated product over shelf life. Both are used for Listeria monocytogenes in ready-to-eat foods.
The EU's Regulation (EC) No 2073/2005 on microbiological criteria is a widely used framework. For ready-to-eat foods able to support Listeria growth, it sets a limit of 100 cfu/g throughout shelf life, where the producer can demonstrate this. The Listeria criteria in this regulation have since been amended, so always work from the current consolidated text. Its Annex II lists the studies that support that demonstration, from product characteristics and literature to predictive modelling, challenge tests and durability studies.
Predictive models
Tools such as ComBase estimate how an organism might grow under given conditions. They help screen recipes and choose test temperatures, but support a study rather than replace one.
How to design a shelf-life study, step by step
- Define the product and conditions: recipe, process, packaging, storage temperature and the intended consumer.
- Identify the hazards: from your HACCP hazard analysis, list pathogens and spoilage organisms that could grow.
- Set the sampling plan: typically at least three production batches, with enough units for each test point and for testing beyond the target date.
- Choose test parameters: microbiological (pathogens, indicators, yeasts and moulds), sensory (appearance, odour, taste, texture) and chemical (pH, water activity, rancidity where relevant).
- Include abuse temperatures: store some samples above the label temperature to reflect real retail and home fridges.
- Set acceptance criteria in advance: use legal criteria, customer specifications or recognised guidelines, and define sensory failure.
- Analyse, sign off and verify: set the date with a safety margin, approve it formally and confirm it with ongoing end-of-life testing.
Where possible, use a laboratory accredited to ISO/IEC 17025:2017 for the relevant methods, and keep the full study file as HACCP validation evidence.
Labelling requirements in the GCC and India
In the GCC, Gulf Standardization Organization (GSO) standards set requirements for date marking. GSO 9 covers labelling of prepackaged foods, and the GSO 150 series on expiration periods of food products is often referenced. National authorities such as the SFDA, Dubai Municipality, ADAFSA and Sharjah Municipality may apply additional requirements, so confirm the current standard with them.
In India, the Food Safety and Standards (Labelling and Display) Regulations, 2020 require date marking on prepackaged food. Confirm which dates are mandatory for your category with FSSAI before printing labels.
Worked example: a chilled cream cake in Sharjah
A Sharjah bakery plans to launch a chilled cream cake: sponge layers, pasteurised whipped cream filling and fresh fruit topping, sold through supermarkets at 0–5 °C. Marketing asks for six days.
The cream and fruit are added after baking, so the QA lead focuses on post-process contamination: Listeria monocytogenes, Staphylococcus aureus from handling, and yeasts and moulds. The product's pH and water activity offer no hurdle against Listeria.
- Samples: three batches, stored at 4 °C, with a set stored at 8 °C as the abuse condition.
- Tests: on days 0, 2, 4, 6 and 7 for Listeria, Enterobacteriaceae, S. aureus, yeasts and moulds, plus a sensory panel.
- Support: a ComBase prediction for Listeria growth in dairy cream at both temperatures.
All pathogen results are satisfactory. At 4 °C, yeasts rise sharply after day 5 and the fruit topping weeps by day 6. At 8 °C, quality fails by day 4. The team sets a use-by of four days, below the last satisfactory point, and adds end-of-life testing of one batch a month.
Marketing does not get six days, but the bakery gets a date it can defend to an auditor and its retail customers.
Common mistakes
- Copying shelf life from a similar product or competitor.
- Testing only one batch, or only at the ideal temperature.
- Using accelerated testing to justify microbiological safety.
- Setting acceptance criteria after seeing the results.
- Treating a predictive model as the full study.
- Not repeating the study after a change of recipe, supplier, packaging or process.
- Judging only sensory quality and ignoring pathogens that cause no visible change.
Key takeaway: Shelf life is a validated food safety decision. Understand what drives deterioration, combine the right study types, set criteria before testing, include realistic abuse, and keep verifying the date once the product is on sale.
Frequently Asked Questions
How do you determine the shelf life of a food product?
Identify the hazards and spoilage mechanisms, then store samples from several batches under intended and abuse conditions. Test them at intervals for microbiological, chemical and sensory change against criteria set in advance. Set the declared date before the first failure point, with a margin, and verify it with ongoing testing.
What is the difference between use-by and best-before?
A use-by date relates to safety and is used for highly perishable foods that could become unsafe after the date, even if they look fine. A best-before date relates to quality: after it, the food may lose flavour or texture but is not expected to be unsafe if stored correctly. Terminology varies by country.
Can accelerated shelf-life testing be used for chilled foods?
Only with great caution. Accelerated testing assumes deterioration speeds up predictably at higher temperatures, which works reasonably for chemical changes such as rancidity in shelf-stable foods. Microbial growth does not scale so simply, and different organisms dominate at different temperatures, so chilled food safety needs real-time studies, challenge tests or durability studies.
How often should shelf life be revalidated?
Revalidate whenever something that affects shelf life changes, such as the recipe, an ingredient supplier, packaging, process or storage conditions. Even without changes, ongoing verification through periodic end-of-life testing and complaint trend review confirms the date still holds. Review frequency should be defined in your food safety management system.
Next steps
Setting and defending shelf life draws on hazard analysis, validation and labelling. Advanced Food Safety Management & Compliance builds these skills for QA professionals, and Food Traceability, Recall & Crisis Management covers what happens when a date or product fails in the market.
For related reading, see our temperature danger zone guide, food traceability and recall readiness and Listeria environmental monitoring in food plants. Not sure which course fits your role? Speak to a counsellor.
Looking for structured certification?
Explore Innoryx courses or speak to a counsellor about the right program for you.