Deliberately putting holes in a perfectly good polythene bag seems a bit of a waste, doesn’t it? After all, the whole point of packaging is to create a barrier – to keep things out and protect what’s inside. So why on Earth would you want to compromise that by poking holes in it?
The answer is in understanding the product you are packaging. For a huge range of goods, a completely airtight seal is actually the worst thing you can do. It creates a tiny, humid microclimate where the product suffocates and rots in its own moisture.
Perforated bags are the simple solution to this problem.
The problem with airtight packaging for some products
The most obvious one is fresh produce. Even after they are harvested, fruits and vegetables are still alive. They respire, taking in oxygen and giving off carbon dioxide and water vapour. If you seal a tomato, a bunch of grapes, or a punnet of mushrooms in a standard, non-perforated polythene bag, that waste gas and moisture has nowhere to go.
The result? The packaging becomes a miniature greenhouse. Condensation forms, creating a damp environment that is a perfect breeding ground for mould and bacteria. The product rapidly decays.
But perforated bags eliminate this problem by allowing for gas exchange.
The balancing act of ventilation
Perforated bags solve these problems by creating a pathway for gas exchange. The holes allow excess moisture and gases like carbon dioxide to escape, reducing condensation and preventing that “greenhouse effect”. This controlled ventilation helps keep produce fresher for longer and stops condensation from ruining sensitive goods.
Beyond food, perforations solve a purely physical problem. When packing large or bulky items, like textiles or soft goods, air can get trapped inside the bag, causing it to balloon. This not only looks messy but also makes the items harder to stack in a box or on a pallet. Perforated bags allow that air to escape easily during packing, helping the bag sit flat around the product and improving overall packaging efficiency.
When microperforations are used, the bag is still dust proof and largely water resistant, as the holes are so small that droplets of water will find it difficult to penetrate them. And that brings us onto the differences in perforations…
Microperforated versus perforated bags: what is the difference?
Not all perforations are the same – and choosing the right type is crucial for your product.
Microperforated bags – for controlling gas and contaminants
Microperforated bags feature tiny holes, often invisible to the naked eye, that are typically measured in microns. These minuscule holes are precision-engineered, often created using very fine needles or lasers.
Because the holes are so small, they allow for a very delicate, controlled gas exchange. This is perfect for highly sensitive products that need to breathe, but also require a strong barrier against contaminants. You will often find microperforated bags used for fresh produce and baked goods, which benefit from the precise balance of oxygen, moisture, and carbon dioxide that microperforation provides. It keeps them fresh without drying out.
But pharmaceuticals and medical devices are one of the main sectors we serve that demand microperforations in their packaging. They allow sterilising gases to escape, or permit a controlled gas exchange to maintain product stability, while still keeping the contents safe from contamination.
Read more: The Power of MAP Packaging
Perforated bags – for maximum airflow
Perforated bags have larger, easily visible holes. These are designed for maximum airflow rather than precision gas exchange.
The larger holes are very effective at preventing moisture buildup and allowing air to circulate. While they offer very low protection against moisture ingress and dust, you just simply wouldn’t use them for anything that needs to stay dry or clean as a priority.
Instead, these bags are for more robust, hardy products that benefit from a lot of ventilation, such as bulky goods that may be damp at the point of packaging (quarried goods, turf, logs and timber, etc.). Think of perforated bags like nets: great for bundling things and lifting them as one, not for sealing them off completely. But where the perforations are much smaller and more uniform than netting, smaller goods can be carried in them.
Comparison chart
| Features | Microperforated bags | Perforated bags |
| Perforation size | Tiny – measured in microns | Large, clearly visible to the naked eye |
| Function | Precision gas exchange, controlled respiration, partial sealing | Maximum airflow, simple ventilation, bundling goods |
| Best for | Delicate produce, baked goods, medical and pharma | Hardy produce, textiles, bulky goods, soft breathable goods |
| Moisture barrier | Good barrier against external moisture and contaminants | Very little protection against external moisture |
| Dust protection | Excellent – holes are too small for dust to pass through | Somewhat effective |
Get custom polythene perforated bags, from NPF Packaging
We hope this explainer for perforated bags helps you choose the right packaging to keep your products fresher, safer, and better presented. If you’re ready to order, get in touch now. Contact us or call 01773 820415 to start.