Tesco has been forced to recalculate its food waste reduction figures after discovering that tens of thousands of tonnes it claimed to have been sent for animal feed was secretly sent to anaerobic digestion.

The supermarket giant, which has been among the leading voices in the call for transparency on food waste reporting, has more than halved its waste reduction figures from 45% between 2016/17 and 2022/23 to just 18%.

Tesco revealed to The Grocer this week that it had ‘terminated’ its contract with the food waste processor after an audit at the end of last year made the discovery. The retailer has since launched an investigation into the issue as it expects figures for this year to be “similarly affected.”

Tesco’s quality, technical, and sustainability director, Claire Lorains, said: “While anaerobic digestion can have a role in recovery of energy and avoids food going to landfill, under the food waste hierarchy, we count food going to anaerobic digestion as waste.

“As we had worked with our former processor over a number of year, we believe it is right to exclude animal feed from our data.”

Last year, Tesco reported more than 35,000 tonnes of food waste in the UK. While the revelation is a blow to the supermarket’s stance on waste processing, industry commentators have praised the retailer for its ‘transparent approach to the discovery’ as well as the swift action taken against the unnamed waste food processing company.

“We are therefore withdrawing our previously reported food waste data, and we expect our reduction this year will be similarly affected,” said Claire.

The supermarket chain become one of the first UK food retailer to align its executive pay performance targets to key sustainability measures in 2022 and at the time detailed plans to halve food waste in its own operations by 2025.