Love them or hate them, mushrooms are one of the world’s most cherished and nutritious food crops. And they are big business – mushrooms boast a £40 billion market globally. Not bad for fungus.
But mushroom packaging has always been a tough nut to crack. The garden varieties of common consumer mushrooms are soft, vulnerable and highly prone to rapid decay after being harvested. For the most part, we’ve addressed the soft and vulnerable aspect of our favourite fungi, by packaging them in HDPE or cardboard cartons for strength. But the rapid spoiling has only recently been solved by food packaging science, saving millions of mushrooms from being wasted.
The answer? Microperforated film; a breathable membrane that keeps dirt out and freshness in. But what is this stuff, how does it work – and why would anyone want holes in their packaging?
What is microperforated film?
Microperforated film is a type of machine film with tiny holes running all the way through it. This might seem odd, given that we like to have perfectly sealed packaging in most industries, but these tiny holes are very useful for packaging some things – like mushrooms.
As soon as mushrooms are harvested, they begin giving off water as vapour. This can condense, allowing water to collect in sealed packaging – and this causes big problems for freshness. Wet mushrooms decay rapidly, becoming slimy and smelly within a matter of days, even in the fridge.
Microperforated films are a clever solution. The tiny holes allow vapour to escape from the packaging and improve air circulation – but they are so small that dirt and even water droplets can’t pass through. This provides an effective seal under normal supermarket and transportation circumstances, holds the produce safely in the packaging and maximises shelf life.
Read more: Polythene in the food industry
Of course, mushrooms aren’t the only products to benefit from microperforated film packaging – freshly baked goods (typically crusty loaves, baguettes, pasties and sausage rolls) are often wrapped in microperf film, to enhance visibility without steaming them into a mushy mess. These films offer better protection and sealing than paper bags, without making the product invisible.
Other uses for microperforated film
Although not something we come across often in our line of packaging work, microperforated film is used as an optical filter for glass and plastics. It can be used as a “frosting” effect for privacy, to control ambient lighting, or for use in optical experiments. PVC is commonly used for its adhesion to glass, but polythene is a viable alternative for covering other optical materials.
So now we’ve got microperforated film covered, let’s talk about perforated film.
The holes in perforated film are bigger and easier to spot, and are usually spaced farther apart. Perforated films are often used in agriculture and horticulture, where perforated films shield plants while controlling the temperature and humidity. The perforations can allow moisture into grow bags while keeping the soil and nutrients inside. In irrigation systems, these holes allow water to percolate into the soil slowly, so it can still be distributed through the whole system.
Learn more: Polythene For Farming And Agriculture
The benefits of using polythene microperforated film
Polythene microperforated films are highly customisable, durable, flexible and versatile over many applications. With additives, UV resistance can be achieved, as well as sub-zero temperature compliance. It’s highly transparent, and the microperforations stop fogging and condensation from appearing inside the packaging.
Polythene is food safe, and odourless, too – unlike rival materials, which can have a certain smell to them. It’s 100% recyclable, oil-safe and professional looking, all while remaining competitively priced.
Microperforated polythene film – for professional packaging
Microperforated films bring controlled ventilation to your packaging. The minuscule holes allow for airflow and moisture escape, while mitigating the effects of dirt, debris and even spills during transport and storage. These films are vital in the food industry, preserving the freshness of some types of produce – but their use extends outside of the supermarket.