How to Set the Shelf Life of Your Food Product (Without a Lab Bill You Can't Afford)

The number you can't just guess

Every product you sell needs a shelf life: the period during which it stays safe and of acceptable quality, expressed as a use by or best before date. Setting it is one of the trickier jobs a small producer faces, because getting it wrong cuts both ways. Too long, and you risk selling unsafe food. Too short, and you waste good product and money.

Shelf life also can't simply be guessed or copied from a similar product. It's something you're expected to set with knowledge of the risks and to be able to justify. Here's how to approach it sensibly, including when you genuinely need a lab and when you don't.

What determines shelf life

A product's shelf life is governed by how quickly it spoils or becomes unsafe, which depends on its characteristics and how it's stored. The main factors are:

Intrinsic factors: the product itself, its pH (acidity), water activity (how much water is available for microbes), salt or sugar content, and preservatives. A high-acid or low-water-activity product (like a jam or a dry mix) is far more stable than a moist, neutral one.
Extrinsic factors: how it's stored and packed, the storage temperature, and the packaging (including vacuum or modified atmosphere packing).
Processing: what your process does to reduce or control microbes, such as cooking, acidifying, or drying.

Together these determine both how long the product lasts and which type of date mark it needs. Understanding your product's intrinsic factors is the starting point: a producer who knows their product is high-acid and low-water-activity already knows it's inherently more stable.

Use by or best before?

The type of date mark follows directly from safety. A use by date relates to microbiological safety and is required for perishable, higher-risk products that can support the growth of harmful bacteria, typically moist, neutral or low-acid, ready-to-eat foods. After the use by date, the food is deemed unsafe. A best before date relates to quality rather than safety, and is used for more stable products that don't become unsafe but do deteriorate.

Choosing the wrong type isn't a technicality; putting a best before on a product that should carry a use by is a genuine safety failure. Our guide to use by versus best before covers this distinction in full.

The types of shelf-life study

Shelf life is validated through one or more types of study, and you don't always need an expensive lab:

Reviewing the science and existing data. For many products, established guidance and data on similar products give a strong, defensible starting point. A producer of high-acid preserves, for example, can draw on well-understood principles about why those products are stable.
Durability (real-time) trials. Storing the product under its intended conditions and assessing it at intervals to see how it holds up over time.
Challenge testing. A laboratory deliberately introduces specific microorganisms to see whether they can grow over the shelf life. This is the gold standard for higher-risk products and is where lab costs come in.
Predictive microbiology. Using validated models to predict microbial behaviour based on the product's characteristics.

The honest position for a small producer is this: for stable, lower-risk products (high-acid, low-water-activity, dried, or high-sugar), you can often set a defensible shelf life through sound reasoning, existing data, and real-time trials, without a large lab bill. For higher-risk, ready-to-eat, chilled products, particularly anything vacuum or modified atmosphere packed, you should take proper advice and may genuinely need laboratory challenge testing, because the consequences of getting those wrong are severe.

The high-risk cases where you must not cut corners

Some products carry risks that demand expert input regardless of budget. Chilled ready-to-eat foods, and especially vacuum-packed and modified-atmosphere-packed products, can support dangerous organisms (including Clostridium botulinum) that grow without obvious signs of spoilage. For these, established best-practice guidance sets cautious limits, and shelf life must be set with full knowledge of the hazards. This is not an area to estimate. Our guide to vacuum packing and food safety explains why these products need particular care.

Document and review it

Whatever route you take, you must be able to justify the shelf life you've set, and you must review it. The justification, your reasoning, data, or test results, forms part of your food safety management system, and an auditor may ask to see it. Crucially, shelf life isn't set once and forgotten: if you change your recipe, ingredients, process, packaging, or storage, you must reassess it, because any of those can change how the product behaves.

This is where shelf life connects directly to your HACCP plan. Shelf life is a product characteristic that feeds into your product descriptions and your hazard analysis, and a recipe or process change that affects shelf life is exactly the kind of change that should trigger a HACCP review. Keeping your product information and the reasoning behind your shelf lives alongside your plan means that when something changes, you have one accurate source to reassess from. FoodSafe holds your product and process information with your HACCP plan, so shelf-life decisions sit alongside the rest of your documented system rather than in a separate file you forget to update.

Set it with knowledge, not hope

Setting shelf life is about matching the date mark to the real safety and quality of your product, justified by sound reasoning and, where the risk demands it, proper testing. For stable, lower-risk products you can often do this affordably and defensibly yourself. For higher-risk and vacuum-packed products, get expert advice and don't economise on safety. Either way, document your justification, review it whenever your product changes, and you'll have shelf lives you can stand behind, to a customer, an auditor, or an EHO.

For how to display the date you've set, see our guide to date marking your products correctly.

Food safety compliance, handled.