Almost 400 workers are facing redundancy as part of plans by Morrisons to shut its Rathbones bakery operation.
Unions have accused Morrisons of throwing "workers on the scrapheap" since its private equity takeover in 2021.
The UK's fifth-largest supermarket said it has started a consultation over the potential closure of the Rathbones own-label bakery operation in Wakefield following a "thorough review".
The move will put the jobs of 378 workers at the site at risk of redundancy.
Morrisons snapped up the bakery business from administration in 2005, but said it has struggled to make it profitable in recent years.
A spokesperson for Morrisons said: "After a period of growth and investment, the business has been loss making for a number of years.
"Although we have tried several routes to return the business to profitability, none have been successful.
"The current proposals do unfortunately mean that colleagues at the site are at risk of redundancy and we will do everything we can to help those colleagues affected, including investigating whether there are any other suitable roles elsewhere in the group."
The retailer, which is owned by US private equity firm Clayton, Dubilier & Rice, said that its 450 in-store Market Street bakeries will not be affected by the potential closure.
It is understood that Morrisons is looking at options to continue making some baked breakfast goods, such as muffins and croissants, at the site, in a move which could maintain some jobs.
Morrisons said it is "considering all alternative options … on how we could change our current business model and safeguard as many jobs as possible".
Sarah Woolley, general secretary of the Bakers, Food and Allied Workers Union, said: "Since Morrisons were bought out by Clayton, Dubilier & Rice in 2021 we have seen the traditional cycle of private equity firm behaviour post-takeover that throws workers on the scrapheap without even a glance back.
"They have asset stripped Morrisons, with our members now bearing the brunt of their mismanagement with this short-sighted decision to close the site.
"This treatment of people is plain wrong and unfair on the hundreds of people who work at the site and who have had their lives turned upside down by this decision."
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