Choosing packaging isn’t just a branding decision — it’s a shelf life decision. The material you put around a product determines how much oxygen, moisture, and light reach it, and those three factors are what drive spoilage, staling, and flavor loss in almost every food category.
This guide breaks down what brand buyers actually need to know: which materials block what, why multilayer barrier films exist, and how to match packaging to a product’s actual shelf life requirement instead of guessing or over-speccing.
Quick Answer
Packaging material affects shelf life mainly through three barrier properties: oxygen transmission rate (OTR), moisture vapor transmission rate (MVTR), and light blocking. Aluminum and tinplate offer near-total barriers against oxygen, moisture, and light. Glass blocks oxygen and moisture just as well, but only tinted or opaque glass blocks light — clear glass lets UV and visible light straight through. Plastics vary widely — PET and multilayer films with an EVOH barrier layer perform well against oxygen, while HDPE blocks moisture but lets gas through. The right material depends on whether your product’s biggest enemy is oxidation, moisture loss, staling, or light-driven nutrient breakdown.
The Three Factors That Actually Degrade Food
Oxygen exposure oxidizes fats and pigments, causing rancidity, browning, and off-flavors — a bigger risk for snacks, coffee, nuts, dairy, and meats than most buyers assume. Packaging with a low oxygen transmission rate (measured in cc per square meter per day) slows this down; a lower OTR number means a better barrier.
Moisture works the opposite way depending on the product: crackers and chips go stale if moisture gets in, while dried fruit or jerky can spoil if moisture escapes. This is measured as moisture vapor transmission rate (MVTR), and it’s often a more critical spec than oxygen barrier for crisp, dry snack categories.
Light, especially UV, degrades vitamins, oils, and pigments — a known issue for products like milk, beer, and oils packaged in clear containers. This is a property of tint and opacity, not of the base material itself: a package can have an excellent oxygen and moisture barrier and still let light ruin the product if it’s clear. Opaque, amber or brown-tinted, or foil-lined packaging is what actually blocks light, regardless of whether the underlying material is glass or plastic.
How Common Materials Compare
PET (polyethylene terephthalate) is transparent, resists moisture and corrosion, and provides a solid barrier against oxygen and CO2 loss, which is why it’s standard for bottled beverages and many perishable-food containers. Like clear glass, clear PET offers little to no light protection on its own.
HDPE (high-density polyethylene) — used for milk jugs and many bags — resists moisture well but has a comparatively weak gas barrier, so it’s a poor choice alone for anything oxygen-sensitive or carbonated.
Glass and lacquered aluminum/tinplate are chemically inert and essentially impermeable to oxygen and moisture, which is why canned goods, coffee tins, and glass jars remain benchmarks for long, unrefrigerated shelf life. But glass and light protection aren’t the same thing: clear glass transmits most UV and visible light, so light-sensitive products (beer, milk, oils, some supplements) need amber, brown, or otherwise tinted glass — or opaque packaging — to actually get protected. Aluminum and tinplate, being opaque, block light by default. The tradeoff for glass and metal generally is weight, fragility (glass) or cost, and shipping expense.
Multilayer flexible films solve the single-material tradeoff by combining layers: an EVOH (ethylene-vinyl alcohol) layer just a few micrometers thick, sandwiched between structural plastic layers, delivers an oxygen barrier dramatically better than standard polyethylene film alone — which is why it’s widely used in flexible pouches for meat, cheese, and other oxygen-sensitive foods. EVOH’s main weakness is that it loses barrier performance when wet, so it’s typically paired with a moisture-blocking outer layer rather than used on its own. Light protection in these films comes from adding an opaque or metallized layer, not from the EVOH itself.
For products that need real shelf-life extension beyond what the base material offers, modified atmosphere packaging (MAP) — replacing in-package air with a low-oxygen gas mix — and vacuum sealing are the two techniques buyers layer on top of barrier materials rather than substitutes for choosing the right material.
Tips / Common Mistakes
Don’t spec packaging by category habit alone — a product’s actual failure mode (rancidity vs. staling vs. moisture loss vs. light degradation) should drive the material choice, not ‘what everyone else in this aisle uses.’
Ask suppliers for actual OTR and MVTR numbers on the specific structure you’re buying, not just the base resin name — the same plastic can perform very differently as a monolayer film versus part of a laminate.
Don’t over-spec a high-barrier structure (like full EVOH multilayer) for a product with a short intended shelf life or that’s sold refrigerated — it adds cost without a meaningful benefit.
Don’t assume glass automatically means light protection — clear glass lets UV and visible light through and offers essentially no shielding for light-sensitive contents. Only tinted (typically amber or brown), coated, or opaque glass actually blocks light; if your product is light-sensitive, that tint or opacity is the spec that matters, not just the choice of ‘glass.’
Factor in real-world handling: a material’s lab-tested barrier value assumes intact packaging — seal integrity, pinholes, and closure quality often matter more to real shelf life than the base material spec.
Explore more: Explore more packaging materials guides.
Packaging Material and Food Shelf Life FAQs
What packaging material gives the longest shelf life?
Aluminum and tinplate offer the best overall barrier against oxygen, moisture, and light, making them the standard for the longest shelf-stable products like canned goods and coffee tins. Glass matches them for oxygen and moisture barrier but only blocks light if it’s tinted or opaque — clear glass does not. Among flexible plastics, multilayer films with an EVOH barrier layer come closest to that oxygen-barrier performance.
What is OTR and why does it matter for food packaging?
OTR (oxygen transmission rate) measures how much oxygen passes through a packaging material over time, typically in cc per square meter per day. A lower OTR means a better oxygen barrier, which slows oxidation, rancidity, and color loss in oxygen-sensitive foods.
Is plastic or glass better for food shelf life?
Glass is chemically inert and has an essentially perfect barrier against oxygen and moisture, but it’s heavier, more fragile, and costlier to ship — and clear glass gives no light protection. High-barrier plastics (like PET or EVOH multilayer films) can approach similar oxygen and moisture performance at a fraction of the weight and cost, though they also need an added opaque or metallized layer if the product is light-sensitive.
Does clear glass protect food from light damage?
No. Clear glass transmits most UV and visible light, so it does little to protect light-sensitive foods and beverages from degradation. That’s why products like beer and some dairy or oil products are packaged in amber or brown glass, or in opaque/foil-lined containers — the tint or opacity is what blocks the light, not the fact that it’s glass.
Does packaging material affect food safety, not just freshness?
Yes — beyond staling and oxidation, poor barrier packaging can let in moisture or oxygen that supports microbial growth, since microorganism growth depends heavily on moisture, oxygen availability, and temperature. Barrier packaging that controls these factors is a food safety tool as well as a freshness one.
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Photo: Chillmedic / CC BY-SA 4.0, via Wikimedia Commons.