We don't sell packaging. We sell shelf life.
Article · Packaging Explained
A vacuum pouch is a multi-layer barrier laminate that holds a vacuum without puncturing or leaking. Air is drawn out before sealing, so the product sits in near-zero oxygen. Typical structures pair a nylon layer for puncture resistance with an EVOH core for the oxygen barrier and a polyethylene sealant that closes the pack.
Most buying guides stop at "vacuum sealing keeps food fresher." That leaves two questions unanswered — what film to actually order, and whether vacuum packing is safe for your product in the first place.
This guide covers the film anatomy, the OTR to specify, when MAP is the better choice, and the chilled-food rule that most packaging suppliers never mention.
A vacuum pouch is a flexible multi-layer bag engineered to survive having the air pulled out of it and then hold that state. It differs from an ordinary pouch in three ways: it resists puncture from sharp or bony product, it maintains seal integrity under negative pressure, and it carries a high enough oxygen barrier that the vacuum still means something weeks later.
The last point is the one that gets missed. Pulling a vacuum removes the oxygen that is in the pack today. It does nothing about the oxygen that permeates through the film over the following months. A vacuum in a low-barrier bag is a temporary condition.
Vacuum packing works on two mechanisms. Removing the air suppresses aerobic spoilage organisms — moulds and many spoilage bacteria — that need oxygen to grow. It also removes the oxygen available for oxidation reactions, which is what causes rancidity in fats, colour loss, and aroma loss in coffee and spices.
The barrier film then does the second job: keeping replacement oxygen out for the life of the product.
That division of labour matters commercially. If your product fails from rancidity at month four in a vacuum pack, the vacuum did its job on day one and the film did not do its job on day one hundred. The fix is barrier, not a better vacuum.
Vacuum packing does not make food shelf-stable. Chilled vacuum-packed product still needs its cold chain, and it still spoils — often without the visual cues you would get in an aerobic pack, because the organisms that make food look obviously spoiled are the ones the vacuum suppressed.
A high-barrier vacuum pouch is typically a PA / EVOH / PE laminate. Each layer does one job, and specifying the pouch means specifying all three rather than asking for a thickness in microns.
| Layer | Material | What it does |
|---|---|---|
| Outer | Polyamide (nylon) | Mechanical strength, puncture and tear resistance during handling and transport |
| Tie | Adhesive resin | Bonds dissimilar polymers together |
| Core | EVOH (ethylene vinyl alcohol) | The oxygen barrier — the layer that actually determines the OTR |
| Tie | Adhesive resin | Bonds the core to the sealant |
| Inner | Polyethylene | The sealant layer — forms and holds the seal, and is the food-contact surface |
The proportions are less intuitive than most buyers expect. According to US Patent 6,015,235 for a puncture-resistant barrier pouch, the EVOH barrier core accounts for around 6% of total film thickness, with each polyamide intermediate layer at roughly 9%. The layer doing the barrier work is among the thinnest in the laminate.
This is why "just make it thicker" is poor specification. Overall thickness does influence OTR, but adding polyethylene adds cost and stiffness without adding much barrier. What changes the oxygen number is the barrier layer itself.
One caveat worth stating: EVOH's oxygen barrier is measured dry and weakens as humidity rises — its OTR can climb several-fold at high relative humidity. That is exactly why the EVOH core sits buried between the hydrophobic PA and PE layers that shield it from moisture. For high-moisture products (meat, cheese) and for retort — where moisture drives through the film during the cook — a single dry OTR figure overstates in-use performance, which is why those duties often move to foil, metallised or AlOx/SiOx barriers.
One structural choice worth flagging: foil-based laminates give near-total barrier but cannot be microwaved and complicate recycling. Foil-free high-barrier structures now reach oxygen levels that used to require aluminium, which is what makes microwaveable and mono-material-leaning vacuum packs feasible. Our high-barrier films cover both routes.
Oxygen-sensitive products such as roasted nuts and ground coffee need an oxygen transmission rate below 1 cc/m²/day, according to industry guidance on film transmission rates. For premium coffee, high-fat products and long export shelf lives, the requirement runs considerably lower than that.
OTR is measured in cc/m²/day, tested to ASTM D3985 or ISO 15105, conventionally at 23 °C and 0% relative humidity. Our OTR & WVTR guide sets out how the numbers are produced and what each barrier class delivers.
Three variables set your actual requirement: how oxygen-sensitive the product is, the pack's surface area relative to its contents, and how long the product has to survive. A 12-month export claim and a 3-month domestic claim on the same product are different film specifications.
Mapped against the BARRIXA™ barrier tiers:
| Tier | OTR (cc/m²/day) | WVTR (g/m²/day) | Typical vacuum applications |
|---|---|---|---|
| PRO | < 0.20 | < 0.20 | Dry fruits, nuts, spices, frozen product |
| PRIME | < 0.10 | < 0.10 | Cheese, processed foods, nutraceuticals |
| ULTRA | < 0.08 | < 0.06 | Premium coffee, high-fat products, foil replacement, long export cycles |
Note how far below the 1 cc/m²/day threshold these sit. That headroom is what turns a short domestic shelf life into an export-viable one — but it should be matched to the requirement, not bought by default. Over-specifying barrier is money spent on protection the product never needed.
Use vacuum when the product is dense, oxidation-sensitive and can be compressed without damage. Use modified atmosphere packaging when the product is soft, respiring, or when you need carbon dioxide actively inhibiting microbial growth rather than just the absence of oxygen.
| Vacuum | MAP | |
|---|---|---|
| Mechanism | Removes air | Removes air, then backfills with a gas mix |
| Primary strength | Oxidation control | Microbial inhibition via CO₂ |
| Product shape | Compressed against the product | Retains headspace and pack shape |
| Equipment cost | Lower | Higher — gas mixing and ratio control |
| Best for | Dry fruits, nuts, cheese blocks, meat cuts, coffee | Fresh produce, bakery, soft or delicate items, retail-presentation packs |
MAP is the more expensive of the two: the machine is more complex and the gas ratio has to be controlled. That cost buys flexibility, because the atmosphere can be tuned per product. Vacuum has no such dial — you get the absence of air and nothing else.
If your product is respiring — fresh fruit and vegetables — vacuum is the wrong tool entirely. The produce continues to consume oxygen and produce CO₂ and ethylene inside a sealed pack, which is what modified atmosphere packaging is designed to manage.
It requires controls. Removing oxygen suppresses aerobic spoilage organisms but creates favourable conditions for anaerobic ones. According to the USDA National Agricultural Library, foodborne botulism from non-proteolytic Clostridium botulinum is the principal microbiological hazard for vacuum and MAP chilled foods.
The figures are specific. According to guidance published by the UK Food Standards Agency, non-proteolytic C. botulinum grows and produces toxin at 3 °C and above, which is within normal chilled storage. On that basis the UK's Advisory Committee on the Microbiological Safety of Food (ACMSF) recommends a maximum 10-day shelf life for vacuum and modified atmosphere packed chilled foods where no other controlling factor can be identified.
A longer chilled shelf life requires at least one additional control. Those recognised in the FSA's vacuum packing guidance include a heat treatment of 90 °C for 10 minutes or equivalent, salt at 3.5% or above in the water phase, reduced pH, and reduced water activity. Check the current guidance for the exact pH and water activity thresholds, as published figures differ between versions and jurisdictions.
These are process controls, not packaging controls. No film specification prevents botulinum growth. The barrier determines how long quality holds; the formulation, the heat step and the cold chain determine whether the product is safe. That distinction belongs in your HACCP plan, and it is the reason a packaging supplier should never be the one setting your chilled shelf life.
The constraint does not apply to ambient dry products such as nuts, dry fruits, coffee and spices, where water activity is already low enough to prevent growth. For those, vacuum packing is a quality and shelf-life decision rather than a safety-critical one.
Lost vacuum is nearly always mechanical — a leak or a puncture — not a barrier failure. Barrier permeation is slow and steady; it degrades quality over months without visibly softening the pack. A pouch that looked tight on Monday and loose on Friday has a hole or a bad seal.
| What you see | Most likely cause | Where the fix lives |
|---|---|---|
| Pack loose within days, random units | Puncture from sharp or bony product | Film — higher nylon content, thicker outer layer |
| Pack loose within days, consistent position | Seal contamination — product or fat in the seal area | Process — fill level, seal bar cleaning |
| Weak or wrinkled seal line | Seal temperature, pressure or dwell time | Process — sealing parameters |
| Slow softening over weeks | Micro-leak through a seal channel | Process or film — sealant layer specification |
| Vacuum holds, but product goes rancid | Oxygen permeation through the film | Film — lower OTR needed |
| Vacuum holds, liquid pools in the pack | Purge from meat or cheese | Normal — consider an absorbent pad |
Read that last-but-one row carefully, because it is the case people misdiagnose most often. If the pack is still tight and the product has still gone off, nothing leaked — oxygen came through the film. Buying a tougher bag will not fix it. Buying a lower OTR will.
Vacuum packing suits dense products that tolerate compression and are damaged primarily by oxygen: dry fruits, nuts and seeds, peanuts, spices, coffee beans, cheese, ready-to-eat meals, meat cuts and confectionery. It does not suit respiring produce, soft or fragile items, or anything whose retail presentation depends on pack shape.
For export, one factor outweighs the rest. Long transit and port time mean the barrier has to hold for far longer than a domestic route requires, which usually pushes the specification a tier higher than the same product sold locally. Whatever shelf life you settle on, validate it in the pack you will actually sell — a study run in a different film does not support your date.
A high-barrier vacuum pouch is typically a PA/EVOH/PE laminate. Polyamide (nylon) provides puncture and tear resistance, an EVOH core provides the oxygen barrier, and a polyethylene inner layer forms the seal and contacts the food. Tie layers bond the dissimilar polymers together.
Oxygen-sensitive products such as roasted nuts and ground coffee need an OTR below 1 cc/m²/day. Premium coffee, high-fat products and long export shelf lives need considerably lower. The exact figure depends on product sensitivity, pack surface area and target shelf life.
Only with controls. Non-proteolytic Clostridium botulinum grows at 3 °C and above, so the ACMSF recommends a maximum 10-day shelf life for chilled vacuum-packed foods unless an additional controlling factor applies — such as a 90 °C for 10 minute heat treatment or salt at 3.5% or above in the water phase.
Almost always a puncture or a seal defect, not the barrier. Barrier permeation is slow and does not visibly loosen a pack within days. Random loose units suggest punctures from sharp product; consistently placed failures suggest seal contamination or sealing parameters.
Yes. Vacuum packing prevents the surface moisture loss that causes freezer burn, because the film sits against the product with no air gap. Choose a structure with adequate low-temperature flexibility so the laminate does not crack during handling.
