Supermarkets should stop selling fresh produce such as apples and potatoes in plastic packaging, research suggests, because it does not make them last longer and adds to pollution and food waste.

The 18-month study by the sustainability charity Wrap, which also looked at sales of bananas, broccoli and cucumbers, debunks the idea that single-use plastic wrappers help prevent waste.

Instead, this packaging often forces people to buy more than they need, increasing the problem of wasted food.

Marcus Gover, Wrap’s chief executive, said that while packaging was important and often carried out a critical role to protect food, its research had found that plastic wrap “doesn’t necessarily prolong the life of uncut fresh produce”, adding: “It can in fact increase food waste in this case.”

Britons throw away almost half a million tonnes of fresh vegetables and salad and a quarter of a million tonnes of fresh fruit – worth a total of £2.1bn – each year because it has gone soft or mouldy, or the date label has expired. This waste is bad for the planet: about one-third of the UK’s greenhouse gas emissions are associated with food and drink.

In the battle with food waste, packaging was found to be a less important part of the picture than other factors, such as enabling people to buy the right amount or how it was stored.

“We found that storing food in the fridge at below five degrees gave days, weeks, and, in the case of apples, months more quality product life,” said Gover. “We found that for most items, the plastic packaging they were sold in made little or no difference to their shelf life.

“In cases where consumers had no choice but to buy more than they needed in pre-packed packaging, this could actually increase food waste,” he added.

Wrap studied the five items: apples, bananas, broccoli, cucumber and potatoes, stored in the original packaging and loose, and at different temperatures.

It calculated that if these five products were sold loose, and the best-before dates removed, it could save more than 10,300 tonnes of plastic and about 100,000 tonnes of food from being wasted each year – the equivalent of 14m shopping baskets of food.

The food waste was prevented because people bought the right amount and used their judgment, rather than date labels, to decide if food was still good. One in 10 people dump groceries based on the date, resulting in good food being thrown out.

Most supermarkets sell some of these items loose already but Wrap, whose work helps shape government policy on sustainability matters, said its research presented compelling evidence for a wider range of fruit and veg to be sold this way.

As people faced rising fuel and food prices, there was a compelling economic as well as environmental case for ringing the changes in grocery aisles, Gover said, and retailers should step up and act on Wrap’s findings. “This helps save the planet and us money at the same time,” he said.

Wrap conceded it would take time for things to change and it will now consult the Food Standards Agency, Defra, and the food industry to make loose produce in supermarkets a reality by 2025.