EVAP Environmental Packaging will only say that its gas-permeable film, which is compostable to EN13432 standards, includes "a high content of a plant-derived renewable resource".
The film is being used by Asda and Tesco to pack potatoes. "Moisture travels through the film, and you can control carbon dioxide and other gas content," said EVAP md Peter Ibbotson.
Tesco claimed the film enabled it to double 'best before' dates on fresh produce. In a statement, potato buyer Andy Blackett called it "a massive breakthrough in the fight against food waste".
Applications would depend on its ability to extend shelf-life, said Ibbotson. "There are some cheese products, for instance, where you want to control gases, and some breads and pastries." In these areas, the extra cost of the film would be offset by reductions in waste, he said. This would not necessarily be true of other applications, such as lidding, which requires a gas barrier.
Longer shelf-life gives flexibility and cuts waste. In a statement from the Waste & Resources Action Programme, director of design and waste prevention Richard Swannell said: "Consumers will have more time to eat the potatoes they buy, which will help reduce the amount we throw away."
Although it was clearly important in the development of the film, EVAP played down the importance of its biodegradability and compostability. "We're talking to the majority of major multiples," said Ibbotson. "The key thing is that we're reducing food waste."
It's important that the film is from renewable resources, he said. But he described composting as "controversial", and pointed out that since successful home composting is largely temperature-dependent, the film is only classified as being industrially compostable.