ZURICH (Reuters) - Swiss chocolate maker Barry Callebaut BARN.S on Thursday signed a partnership with Dutch No.1 retailer Albert Heijn to make its private-label chocolate fully traceable from 2019, reflecting consumers' growing interest in ethical sourcing.

FILE PHOTO: The logo of chocolate and cocoa product maker Barry Callebaut is pictured during the company's annual news conference in Zurich, Switzerland November 7, 2018. REUTERS/Arnd Wiegmann/File Photo

From March 2019, Albert Heijn’s private-label brand “Delicata” will be made from fully traceable cocoa, bought at a higher price from ethical chocolate company Tony’s Chocolonely’s partner cooperatives in Ghana and Ivory Coast, the three partners said in a statement.

Barry Callebaut has been making chocolate for both Albert Heijn and Tony’s Chocolonely for years and will in the future use the separate sourcing chain it set up for Tony’s to make Albert Heijn’s chocolate, representatives of the three companies told Reuters on a call.

"The new Delicata chocolate will have the yellow-orange label with the open chain Tony's uses to indicate to consumers it was sourced sustainably," said Jeroen Hirdes, responsible for chocolate sourcing at Albert Heijn, which belongs to grocery group Ahold Delhaize AD.AS.

As consumers increasingly care more about how their food and drink is produced, companies are trying to make their supply chains more sustainable and transparent.

Hirdes said Albert Heijn would pay Barry Callebaut a bit more for using traceable chocolate from Tony’s “open chain”. It will pass on part of the costs to consumers by increasing prices for its Delicata range that has annual sales of around 30 million euros ($34 million). He was not more specific.

Barry Callebaut, which also supplies chocolate to Nestle NESN.S and Mondelez MDLZ.O, has vowed to eradicate child labor from its supply chain by 2025. It hopes more of its customers will follow the Dutch supermarket chain's example.

“The bigger the scale, the more efficient it becomes. We invite others to join,” said Wim Debedts, sales director Benelux & Nordics at Barry Callebaut.

Henk Jan Beltman, chief chocolate officer at Tony’s Chocolonely, which has turned its “slave-free” chocolate into a commercial success, said industry partnerships were key to accelerating sustainability in the whole sector.

“You can only have an impact if you work together,” he said.

Tony’s generated a net profit of 2.7 million euros on net revenue of 44.9 million in 2016/17.