Shelf Life Testing of Food Products

A shelf-life study answers one question: how long can this product be stored, under stated conditions, and still be safe and acceptable? The answer sets the "best before" or "use by" date printed on the pack, and it is what a buyer, an auditor or a regulator asks for when you change a recipe, a pack or a process.

Auriga Research runs shelf-life determination for food and beverage products. Samples are tested at defined intervals, and the results are turned into a scientifically supported expiry date recommendation.

Shelf-life work draws on the rest of our food scope. Food microbiology testing covers spoilage organisms and pathogens, water activity testing shows how much of the water in a product is available for microbial growth, and nutritional testing supports the values on the label.

There are two ways to run a study, and Auriga offers both.

• Real-time study: the product is stored under its normal storage conditions and tested at set intervals until it fails or reaches the claimed shelf life. It is the most direct evidence, but it takes as long as the shelf life itself.
• Accelerated study: the product is stored under harsher conditions so that change happens faster, and the result is used to estimate the shelf life at normal conditions. It gives an answer sooner and is usually confirmed by a real-time study.

The right choice depends on the product, its packaging and how soon the date is needed. An accelerated study suits a launch deadline, a real-time study suits a product that will stay on the market for years, and many brands run both. Tell us the product, pack and storage claim when you ask for a quote, and we will recommend the design.

The parameters depend on the product. Depending on the product, Auriga tests the following in a shelf-life study:

• water activity;
• rancidity;
• free fatty acids;
• water content;
• microbiology, including bacterial and fungal counts;
• pH; and
• heavy metals, for products in metal packs.

Other safety and quality parameters that apply to the product are tested as per the applicable FSSAI requirements. Your single point of contact confirms which parameters apply to your product when the study is planned.

The results for these parameters over the whole period of the study are summarised in the shelf-life report, described further down this page. For more on the tests themselves, see food microbiology testing and heavy metal testing in food pages.

FSSAI does not set one fixed number of weeks for a shelf-life study. Its rule is about the end point: the stability protocol should extend to the end of the shelf-life period, with the test intervals (time points) and storage conditions written into the protocol and the results formalised as a report. So the length of a study is the shelf life you want to claim. A product with a six-month best-before date is followed for at least six months, and one with a twelve-month date for at least twelve.

Sources: FSSAI, Guidance Document on Food Safety Management Systems for nutraceuticals, section D, Stability Programme; FSSAI, Guidance Document on Food Safety Management Systems for milk and milk products, on the manufacturer determining shelf life and storage conditions.

The same FSSAI guidance makes the manufacturer responsible for determining the shelf life and the storage conditions, and treats the storage conditions as part of the shelf life. At Auriga the study begins by testing the product up to the best-before date you have estimated. What happens next depends on the results at that point:

• if the product still meets its acceptance criteria, for example the microbiological limits for pathogens, the study can carry on, and testing continues until one of the criteria is finally exceeded;
• if the product has already fallen outside a criterion by the estimated date, the study stops there;
• in that case you can change the formulation and run the study again, or accept a shorter shelf life based on the earlier test points.

Whichever date the data supports, a safety margin is taken off it, so the date printed on the pack is not set at the very edge of what the product survived. An accelerated study, run under harsher storage conditions, gives an earlier estimate, while real-time data over the full shelf life remains the reference. Tell us the date you are aiming for, the pack and the storage condition, and we will propose the test points and the duration with the quote.

Date marking is one of the mandatory declarations on a pre-packaged food label in India. Our guide to FSSAI labelling requirements lists all fourteen, and the shelf-life report supports the date you print.

The Auriga shelf-life report gives:

• a full summary of the results over the period of the study;
• a statement of no significant change; and
• a predicted shelf life.

Keep the report with your product file, so that the date on the pack is backed by data and you can show how it was set when a buyer or an auditor asks. Many brands pair a shelf-life study with nutritional value testing, so the label values match the product as it is eaten.