We don't sell packaging. We sell shelf life.
Article · Packaging Explained
Shelf life testing measures how long a product stays safe, nutritious and acceptable under defined storage conditions. Validation is the step after it: proving to a regulator or a buyer's QA team that the date printed on your pack is supported by evidence. Most food businesses do the first and assume the second follows.
There is a catch that costs exporters more than anything else in this process. A shelf life result is only valid for the exact pack it was tested in. Change the film, the thickness or the laminate structure, and the study no longer supports the date.
This guide covers how testing works, when accelerated testing is legitimate, how to read a failure — and what your shelf life target means for the barrier you need to buy.
Shelf life testing is a structured storage study that measures how a packaged product changes over time under defined conditions. It runs four kinds of test in parallel: microbiological, chemical, sensory, and physical or packaging integrity. The output is the point at which the product stops meeting its specification.
Two words get used interchangeably and shouldn't be.
Determination is finding out how long the product lasts. Validation is proving the claimed date is supportable — a written protocol, raw data, and a clear derivation of the label claim from the results. GFSI auditors and regulators ask to see the second. The FSAI's Guidance Note 18 on validation of product shelf-life is the most comprehensive publicly available methodology, and although it is written under EU law, its study design principles travel well.
Eurofins groups the parameters of shelf life testing into microbiological stability, chemical stability, sensory quality, physical stability, nutritional stability, and packaging performance. That last category — barrier properties, seal integrity, migration — is the one most commonly skipped, and it is the one that determines whether the other five hold.
Real-time testing stores product at its actual intended conditions for the full claimed shelf life plus a margin. Accelerated shelf life testing (ASLT) raises temperature, humidity or light exposure to force degradation faster, compressing months into weeks. Real-time gives you the defensible claim. Accelerated gives you a fast estimate to develop against.
Common ASLT conditions for shelf-stable products are 30 °C, 35 °C and 40 °C at 75% relative humidity, according to United Food Labs (2026).
| Real-time | Accelerated (ASLT) | |
|---|---|---|
| Conditions | Intended storage conditions | 30–40 °C, typically 75% RH |
| Duration | Claimed shelf life + 25% | Weeks |
| Defensible to auditors | Yes — this is the validation record | As supporting evidence only |
| Valid for perishables | Yes | No |
| Best used for | The final claim | Development, screening, reformulation |
| Main risk | Time and cost | Wrong failure mode, wrong answer |
The honest position is that ASLT is a development tool, not a substitute. Campden BRI's Bijol Bakhai and Linda Everis wrote in March 2025 that accelerated testing suits ambient and dry products — canned foods, UHT milk, high-acidity sauces, dry snacks, biscuits, powders and cakes — but should not be used for perishable foods requiring a "Use by" date, because microbial growth rates change unpredictably under temperature stress.
Their sharper warning applies to every product: "not all relevant microorganism growth and chemical reactions will speed up at the same rate." Heat can change which organisms grow and force failure modes that would never occur on a real shelf. Campden BRI's position is that the acceleration method itself must be proven valid by modelling accelerated data against real-time data.
Q10 is the factor by which a reaction rate changes for every 10 °C rise in temperature. It is what converts an accelerated result back into a real-world shelf life. For most food products Q10 falls between 2 and 3, meaning deterioration doubles or triples per 10 °C — but across all degradation pathways it ranges from 1.5 to 4.
The factor is calculated as:
Q10 = (R₂/R₁)^(10/(T₂−T₁))
And the extrapolation back to real conditions:
Real-time shelf life ≈ ASLT shelf life × Q10^((T_accelerated − T_storage)/10)
Say your product fails at 6 weeks in an accelerated study at 40 °C, and real storage is 25 °C. The temperature difference is 15 °C.
| Assumed Q10 | Calculation | Predicted real shelf life |
|---|---|---|
| 2 | 6 × 2^1.5 | ≈ 17 weeks (about 4 months) |
| 3 | 6 × 3^1.5 | ≈ 31 weeks (about 7 months) |
Same product, same test data, same maths. The only thing that changed was an assumption — and the answer moved by three months.
This is why Q10 has to be determined for your product from at least two accelerated temperatures, not taken from a textbook. A date claim built on a borrowed Q10 is a guess wearing a lab coat.
You decide before the study starts, by writing end-of-life criteria: the specific thresholds at which the product is no longer acceptable. Without them, a shelf life study produces a pile of data and no conclusion, because "failure" becomes a matter of opinion at the end.
FSNS groups the criteria into three categories:
Water activity deserves its own threshold because it governs both safety and texture. AQUALAB's published limits put mould growth in the range aw 0.62–0.97 and bacterial growth at aw 0.87–0.97, with no microbial growth below aw 0.60. If your product sits at aw 0.55 on day one, the question is not whether it is safe today but how long your packaging keeps it below 0.60.
The final claim is not the failure point. Identify the earliest failure across all three categories, then apply a safety margin — FSNS notes this is commonly a 10–25% reduction from the technical end-of-life point — and round to a practical date. A product that technically holds for 83 days is labelled 75 days, not 83.
Shelf life testing in real time holds product at its intended conditions and tests it at scheduled pull points across and beyond the target date. United Food Labs sets those pull points at 0%, 25%, 50%, 75%, 100%, 110% and 125% of the target shelf life. Testing past 100% is what tells you whether your margin is real.
Two conditions have to be met before you start. The recipe and the process must be final, because changing either changes the answer. And the samples must be in the exact packaging that will be sold — not a similar pouch, not a lab bag.
Sample numbers vary by product, lab and claim; there is no universal figure, so agree it with your testing lab rather than assuming a standard. Alongside the storage trial, two further techniques are often used: challenge testing, where product is deliberately inoculated to validate safety, and predictive microbiology, which models growth as supporting evidence. Neither replaces the storage study.
Your shelf life target sets a barrier specification. The product spoils when enough oxygen or moisture has crossed the film, so the permeability of the pack, its surface area and the storage duration together determine whether the target is reachable. A 12-month claim and a 3-month claim on the same recipe are different packaging problems.
Two numbers describe that barrier:
Lower values mean slower ingress and a longer achievable shelf life. As AQUALAB puts it, the driving force for water movement through packaging is the difference in water activity inside and outside the pack — so a dry product in a humid port warehouse is under continuous pressure that a bench test at 50% RH never sees.
This is where the shelf life result becomes a purchase decision. Matching the barrier to the requirement — rather than over-specifying it — is the whole idea behind the BARRIXA™ barrier tiers:
| Tier | Barrier class | OTR (cc/m²/day) | WVTR (g/m²/day) | Typical products |
|---|---|---|---|---|
| SMART | Smart barrier | < 0.50 | < 5.00 | Dry foods, bakery, confectionery, MAP produce |
| PRO | High barrier | < 0.20 | < 0.20 | Snacks, spices, coffee, tea, hot-fill, frozen |
| PRIME | Very high barrier | < 0.10 | < 0.10 | Dairy, processed foods, nutraceuticals |
| ULTRA | Ultra high, near aluminium | < 0.08 | < 0.06 | Retort, vacuum, premium coffee, baby food |
Over-specifying is a real cost. A dry snack in an ULTRA structure will hold its date, and you will have paid for barrier the product never needed. Under-specifying costs more — a failed date claim, a rejected consignment, and a study to run again. Our OTR & WVTR guide sets out how the figures are measured and what each class delivers.
Yes. Revalidation is required any time ingredients, process parameters or packaging change in a way that could affect safety or quality — and a film change is a packaging change. A different structure has a different OTR and WVTR, so the ingress rate your original study measured no longer applies.
This is the most expensive quiet mistake in the process. A buyer switches to a cheaper laminate to save a few paise per pouch, keeps the same date on the label, and the study on file no longer supports it. Nothing looks wrong until product fails in a container or an auditor asks which pack the data came from.
It applies more widely than most teams assume. Changing thickness, changing the sealant layer, moving from foil to a foil-free structure, or switching supplier for a nominally equivalent film all change the barrier. If you are considering a change, get the OTR and WVTR of both structures and compare them before you compare prices.
A product that fails inside its claimed shelf life has failed for one of three reasons: formulation, process, or packaging. The failure mode usually tells you which — and it is worth diagnosing before you change the recipe, because the recipe is often not the problem.
| What you see | Most likely cause | Where the fix lives |
|---|---|---|
| Rancid or cardboard off-flavour in fatty products | Oxygen ingress | Packaging — lower OTR |
| Loss of crispness, soft or limp texture | Moisture gain | Packaging — lower WVTR |
| Surface mould | aw risen above the mould threshold | Formulation or packaging |
| Colour fading or light-struck flavour | Light exposure | Packaging — metallised or opaque |
| Swollen or gassing packs | Microbial growth, or a seal defect | Process or seal integrity |
| One batch fails, others hold | Process variation | Process |
| Every batch fails at a similar point | Barrier under-specified, or formulation | Formulation or packaging |
Note how many rows point at the pack. In dry, fatty and moisture-sensitive products, oxygen and moisture ingress are the dominant failure routes — which is why a reformulation exercise sometimes fixes nothing, and a barrier change fixes everything.
FSSAI requires packaged food to carry a "Best Before" or "Use By" date reflecting how long the product stays in good condition under recommended storage. For imports into India, Eurofins notes that products must retain not less than 60% of their shelf life at the point of customs clearance.
That 60% rule is a commercial constraint, not a labelling footnote. A product with a 6-month claim must clear customs with 3.6 months remaining — so shipping time, port delays and buyer inventory all eat into a window that started at the factory. Exporters facing that rule usually need a longer validated shelf life than their domestic market requires, and that means a higher barrier tier.
The date format follows the claim length: products with a shelf life of up to three months use DD/MM/YY, while those exceeding three months may use month and year. FSSAI also publishes reference shelf lives for some categories — frozen meat at −18 °C, for example, is treated as 12 months.
For export beyond India, the same study will usually be read against EU Regulation 1169/2011, US 21 CFR Part 101 or Codex standards. The underlying study design is the same; the labelling rules differ.
Not for the final claim. Accelerated testing gives a fast estimate for development, but Campden BRI's 2025 guidance states it should not be used for perishable products carrying a "Use by" date, and that any acceleration method must be proven valid against real-time data. Auditors expect real-time results as the validation record.
A real-time study runs for the claimed shelf life plus a margin, since pull points extend to 125% of the target. A 12-month claim therefore takes about 15 months of storage. Accelerated studies compress this to weeks, which is why most manufacturers run both — ASLT to launch, real-time to validate.
Set end-of-life criteria before the study begins: microbiological limits, chemical and physical limits such as peroxide value, pH and water activity, and sensory cut-offs. Take the earliest failure across all three categories, then apply a safety margin — commonly a 10–25% reduction — to reach the printed date.
Yes. Revalidation is required whenever packaging changes in a way that could affect quality or safety. A different film has a different OTR and WVTR, so oxygen and moisture ingress rates change and the original study no longer supports the claim. Compare the barrier figures of both structures before switching.
There is no single answer, because it depends on the product's oxygen sensitivity, the pack size and surface area, and storage conditions. As a starting point, dry ambient products often sit in the OTR < 0.50 cc/m²/day range, while oxygen-sensitive products such as premium coffee, retort meals and baby food typically need below 0.08. The shelf life study confirms it.
