The date printed on a food pack is a claim. Like any claim, it should be based on evidence. In practice, a significant share of shelf life figures on new Indian food products are set by looking at what a competitor printed.
That works until it does not, and when it fails it fails in the market, with your name on the pack.
What shelf life actually means
Shelf life is the period during which a product remains safe and retains its intended sensory and nutritional characteristics under stated storage conditions.
Three separate things are bundled in there, and they usually fail at different times:
- Safety. Microbiological growth. Absolute, and non-negotiable.
- Sensory. Flavour, colour, texture, aroma. Usually the first to go.
- Nutritional. Vitamin degradation, particularly relevant where you have made a nutritional claim on the label.
A product is frequently perfectly safe long after it stops being pleasant. Shelf life is set by whichever fails first, and for well-processed shelf stable food that is nearly always sensory.
The failure modes worth knowing
Lipid oxidation. Fats and oils oxidise, producing the rancid note that ends most snack and flour products. Accelerated by heat, light, oxygen and metal ions. This is what kills millet flour, nut products and fried snacks.
Maillard browning. Reducing sugars react with amino acids over time, darkening the product and shifting flavour. Slow at ambient, much faster in a warm warehouse.
Moisture migration. Water moves within a product or through packaging, softening what should be crisp and hardening what should be soft.
Enzymatic activity. If enzymes were not properly deactivated during processing, they keep working. This is why blanching before freezing is not optional.
Package interaction. Migration between product and pack, or barrier failure letting oxygen or moisture in. The pack is part of the shelf life system, not a container for it.
Accelerated studies
Storing product at elevated temperature to speed up degradation, then extrapolating back to ambient.
The rule of thumb is that reaction rates roughly double for every 10°C increase, so product held at 45°C ages at roughly four times the rate of product at 25°C. Twelve weeks at 45°C approximates around twelve months at ambient.
Why it is useful: results in four to twelve weeks rather than a year. It lets you launch without waiting out the full claimed shelf life.
Where it misleads: the extrapolation assumes the same degradation mechanisms dominate at both temperatures, and that assumption breaks in specific and predictable cases. Products with fat that changes phase, products where a different reaction takes over at higher temperature, and anything where the packaging behaves differently when warm.
Accelerated studies are an indication, not proof. Treat them as a screening tool.
Real time studies
Store the product under the conditions you intend to claim, and test at intervals across the full period.
Why it is definitive: it measures the actual thing rather than a proxy.
Why it is awkward: claiming eighteen months means an eighteen-month study.
The practical approach used across the industry is to run both. Launch on the accelerated result, run the real time study in parallel, and confirm or adjust. That is the responsible route, and it means you find out from your own samples rather than from a distributor.
What gets measured
A proper study samples at defined intervals (typically 0, 1, 3, 6, 9 and 12 months) and tests:
- Microbiological: total plate count, yeast and mould, and pathogens relevant to the product and process
- Chemical: peroxide value and free fatty acids for fat-containing products, moisture, water activity, pH
- Sensory: a trained panel, scored against a defined reference, not one person's opinion
- Physical: texture, colour measurement, separation, package integrity
For retort and canned products specifically
Shelf stable low acid foods have an additional, non-negotiable layer: the process itself must be validated.
The F0 value expresses the lethality delivered by the thermal process in minutes-equivalent at 121.1°C. For low acid foods, a minimum F0 of 3 is the widely accepted floor for commercial sterility, with many processors targeting higher for a safety margin.
This is established by heat penetration study: thermocouples in the slowest heating point of the pack, in the actual product, in the actual pack format, in the actual retort. It is not transferable between products or pack sizes. A schedule validated for a 300 g pouch does not apply to a 500 g pouch.
Ask your manufacturer for the recorded F0 values on your batches. A plant that cannot produce them is not running a validated process, and the fact that nothing has gone wrong yet is not evidence that it will not.
What to ask for
- What shelf life have you validated for this product, by which method?
- Can I see the study data?
- What storage conditions does the claim assume, and is that stated on the pack?
- For thermally processed products: what is the F0, and how was the schedule established?
- Will you run a real time study in parallel with launch?
If a manufacturer cannot answer these, the number they are proposing for your pack is a guess. It may well be a good guess. It is still not evidence, and it is your brand on the pack.
*Every shelf stable product we manufacture runs against a documented process schedule with recorded F0 values supplied per batch, and we run accelerated and real time studies as part of development. Talk to our technical team.*
Want this applied to your product?
Describe what you are making and we will come back with an MOQ, a lead time and an honest view on whether the format you have in mind is the right one.
