How to specify food packaging barrier performance
Specify oxygen and water vapour transmission limits with the test method, units, temperature and humidity. Require evidence for the complete sealed pack, then validate it with your actual food and filling process over the intended shelf life. Cambridge China Bridge can help coordinate factory samples and checks through its staff in China.
Start with the food and its failure points
Describe the food, fill quantity, intended shelf life, storage and distribution conditions, and whether the claim applies before or after opening. Identify what ends acceptable life: loss of crispness, drying, oxidation, flavour change or a food safety concern. Ask your food technologist to turn those failure points into measurable acceptance criteria before choosing a packaging structure.
Avoid specifying only “high barrier”. Ask the laboratory and packaging supplier to propose moisture and oxygen limits that can be checked against food trials. Record the full material structure, layer thicknesses, pack dimensions and closures. Use the flexible pouch sourcing guide for the wider purchasing brief.
Make transmission results comparable
For oxygen transmission rate and water vapour transmission rate, specify the named test method and edition, units, temperature, relative humidity on each side, gas composition and pressure conditions. Record specimen conditioning, which surface faces the food, and whether the test uses flat material or a formed pack. Ask the laboratory to confirm that the method suits the material and expected barrier level.
State whether the result is expressed per unit area or per complete pack over time. Agree maximum limits, sampling, measurement uncertainty and the decision rule for borderline results. Do not compare supplier figures measured under different conditions as if they were equivalent. A result below the instrument’s reporting limit does not establish that transmission is absent.
Include the complete pack and its seals
Request complete-pack transmission testing that includes the body, lid, seams, seals, zipper or spout, as applicable. A flat-film report leaves other entry paths unassessed. Ask the laboratory to explain which components its test includes and how the specimen is closed. Treat material-area calculations as screening estimates until complete-pack results support them.
Agree separate seal-strength and leak-integrity checks. A strong seal can still contain a channel, and a leak check does not quantify transmission through intact material. Trial the actual sealing equipment, recording temperature, pressure, contact time and cooling. Include folds, product contamination at the seal and handling damage in the trial plan. Ask for component comparisons where you need to identify the seal’s contribution.
Trial production packs with the actual food
Fill packs with your actual recipe using the intended process, fill quantity and headspace. Include any gas flushing or absorbers in the trial. Agree storage conditions, review intervals and failure criteria with the food technologist. Track relevant changes in moisture, texture, flavour, oxidation, headspace gas and microbiological condition through the intended shelf life.
Include packs exposed to representative transport and handling, using the distribution packaging test guide. Investigate failures against seal records and material results. Treat accelerated testing as supporting evidence unless its relationship to actual storage has been validated. The Food Standards Agency notes that packaging methods can affect food hazards; ask a food safety specialist to assess vacuum or modified-atmosphere changes.
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Keep suitability and production approval separate
If you package food yourself, UK government guidance says you must use packaging suitable for food use. Barrier performance alone does not establish that suitability. Review the intended food contact, filling temperature and storage use separately, with the plastic food-contact declaration guide where relevant.
Approve an identified pack specification and trial report before bulk production. Link reports to material batches, pack drawings and sealing records; retain samples and raw results. Require review before changes to layers, thickness, adhesives, closures or sealing settings. Cambridge China Bridge’s staff in China can help collect factory records and coordinate samples against the agreed brief.
Frequently asked questions
What barrier value should I specify for food packaging?
Start with the food’s failure criteria and intended shelf life. Have a food technologist and laboratory propose limits, then confirm them through complete-pack tests and trials with the actual food.
Is a film barrier report enough for a finished pouch?
Request complete-pack evidence as well. Flat-film results leave seals, seams, closures and damage unassessed. Check exactly what the laboratory’s pack test includes.
Can I compare barrier figures from different suppliers?
Only after checking method, units, temperature, humidity, gas and pressure conditions, specimen structure and reporting basis. Ask for comparable testing where these differ.
Does a leak test prove the food’s shelf life?
A leak test checks integrity under its stated conditions. It does not establish material transmission, food-contact suitability or shelf life. Validate the filled pack with the actual food.