Pet food is one of the most demanding categories in flexible packaging. Kibble is abrasive, treats are oily, and both sit on a shelf for months while a customer opens and reseals the same bag dozens of times. This guide covers the structure decisions that keep pet food fresh, the format that fits each fill weight, and the checks worth doing before you print.
Three enemies of pet food — all packaging decisions
1. Oxygen and fat rancidity
Kibble and treats are sprayed with fats and oils. Those fats oxidise, and oxidised fat does not just shorten shelf life — it reduces palatability. The pet stops eating, and the retailer returns the case. Oxygen protection comes from a metallized or foil barrier layer, not from a thicker sealant.
2. Moisture migration
Soft treats want moisture kept in. Dry kibble wants moisture kept out. Both are MVTR (moisture vapour transmission rate) problems, and they are solved with different structures. A single film rarely does both well — if you sell both product types, expect two specifications.
3. Puncture and burst
A 5 kg bag of kibble gets dropped onto a pallet corner in a warehouse. If the sealant layer is too thin or the seal is set too hot, you find out from your customer. Heavy fills need higher-gauge sealant, rounded seal corners and a tested seal window.
Format by fill weight
| Fill weight | Recommended format | Why |
|---|---|---|
| 50–500 g (treats, toppers) | Small stand up pouch with zipper | Retail shelf presence, low unit cost, resealable |
| 1–3 kg | Gusseted stand up pouch | Best unit cost per litre, stands on shelf without support |
| 5–15 kg | Flat bottom (8-side seal) bag | Square base stacks and palletises efficiently, four printable panels |
| Single serve / sample | Flat sachet / 3-side seal | Lowest material cost, ideal for trials and sampling |
For larger fills, flat bottom bags for pet food usually win on pallet efficiency even at a slightly higher unit price — more bags fit per case, and the bag does not slump on the shelf.
The detail most brands under-spec: resealability
A large share of pet food packaging complaints are not about freshness at all — they are about closing the bag. A zipper that fails on day three leaves stale kibble, and the customer notices. Two practical rules:
- Test the zipper with the real fill weight, not with an empty bag
- For fills above 5 kg, consider a heavier zipper profile or a hook-and-loop closure rather than a standard press-to-close zipper
Barrier structure: what each layer does
A typical pet food pouch is a three- or four-layer laminate:
- Outer print layer (PET/BOPP) — graphics, scuff resistance
- Barrier layer (metallized PET or aluminium foil) — oxygen, light, aroma
- Sealant layer (PE/CPP) — seal integrity, product contact, puncture resistance
- Optional matte or soft-touch finish — shelf differentiation
Since these principles are shared across the category, our stand up pouch materials guide covers the layer logic in more depth.
Shelf-life and compliance checks
- Ask for OTR and MVTR figures for the film you are buying
- Run a real shelf-life test: fill the bag, seal it, and store it under the conditions your product will actually see
- Confirm food-contact compliance for the sealant layer, and keep declarations on file
- Include the mandatory label panels: guaranteed analysis, feeding guide, batch/lot code, best-before
- If you export, check destination labelling rules — they frequently differ from your home market
Specifying the bag: a practical order
- Fill weight and product format (kibble, soft treat, powder)
- Required shelf life → choose the barrier layer
- Distribution route → choose film gauge and seal specification
- Closure preference → zipper, hook-and-loop, or none
- Artwork and panel layout → decide before plates are made
- Sample and test with real product
Getting these in this order avoids the most expensive mistake in the category: printing thousands of bags on a structure that fails the 5 kg drop test.
Start with a sample, not a container
Most factories still ask for 5,000–10,000 bags before they will print. We produce custom stand up pouches and flat bottom pet food bags from MOQ 1 piece with 7-day production and DDP shipping worldwide, so you can fill a finished bag with your own kibble and test it before committing to volume.
FAQ
What thickness should a 5 kg dog food bag be?
Most 5 kg retail bags are built on a 5 mil structure with a heavier sealant layer and a reinforced zipper. The critical variable is seal strength and puncture resistance, not overall gauge.
Are stand up pouches or flat bottom bags better for pet food?
Up to about 3 kg, stand up pouches offer the best unit cost and shelf presence. Above 5 kg, flat bottom bags stack and palletise better.
Can the same bag be used for dry kibble and soft treats?
Rarely well. Kibble needs a moisture barrier outward; soft treats need moisture retained. Expect two different structures.