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Sainsbury's has become the latest supermarket to target packaging waste, pledging to halve the amount of plastic used in its stores by 2025.

Its customers will have to change their behaviour to achieve the "bold ambition" it said, for example by buying milk in plastic pouches.

It is also inviting the public and business partners to submit new ideas.

"Reducing plastic and packaging is not easy," said Mike Coupe, Sainsbury's chief executive.

"We can't do this on our own and we will be asking our suppliers and our customers to work with us."

MPs said this week reducing packaging should be the priority for retailers, rather than replacing plastic with compostable or recyclable alternatives.

The infrastructure is not in place in the UK to dispose of compostable or biodegradable materials effectively, parliament's committee for environment, food and rural affairs found. The committee said wider environmental considerations also needed to be taken into account when replacing plastic packaging, including its carbon footprint.

Bring your own

On Friday, Sainsbury's is meeting with food manufacturers, packaging suppliers, material scientists and the waste and recycling industry to kick-start the process of identifying new solutions.

However the supermarket said it was already rolling out some measures, including removing all plastic bags from its fruit and veg sections by the end of this month.

Instead customers will be invited to bring their own bags, buy reusable bags made from recycled plastic bottles, or put a price sticker onto loose items.

Image copyright Sainsbury's Image caption Sainsbury's will sell reusable bags for fresh produce

The supermarket considered introducing paper bags, but spokeswoman, Rebecca Reilly said the net impact would have been worse for the environment.

"There's the deforestation link, and they are heavier and bulkier [than plastic]. They take up space in transport, so there are knock-on carbon emissions," she said.

Sainsbury's will encourage customers to bring their own containers for products from shampoo to raw meat and fish, and will sell more products loose by weight, something Waitrose began trialling earlier this year.

Bags of milk

In many areas it was a question of reducing plastic rather than eliminating it, suggested Ms Reilly. For example milk might be sold in pouches, using less plastic than the current bottles.

But Helen Bird from packaging campaign group, Wrap, said plastic milk bottles were one of the items being widely recycled in the UK.

Plastic pouches aren't currently recyclable, she said, although they would probably produce lower carbon emissions.

But she praised the scale of Sainsbury's ambition and said accepting that it did not yet have all the answers was a sensible approach to the challenge ahead.

"We need to not take decisions like this lightly," she said. "To achieve this they'll need significant levels of innovation.

"They'll also require suppliers to come to them with fresh business models for how they can deliver products to customers in a way that will not have a significant effect on prices as well as carbon and food waste implications."