Mondelēz International has announced plans to close cookie baking facilities in Atlanta and in Fair Lawn, N.J.

The two plants are too old continue running, and their production will be shifted to remaining Mondelēz plants and to contract manufacturers, the company said in a statement. Production at both sites is scheduled to cease by the end of summer.

“Both Fair Lawn and Atlanta are no longer strategic assets from a geographic footprint perspective, and both face significant operational challenges, including aging infrastructure and outdated production capabilities, which would have required significant investment to bring them to the modernized state required for the future,” the statement says. An Oreo cookie “line of the future” at the Fair Lawn facility will be relocated to a factory in Richmond, Va.

The closure of the Fair Lawn plant, which had been Mondelēz’s largest producer of Oreo cookies, will put about 600 people out of work, while the Atlanta closure will affect more than 400 people.

The Fox affiliate in Atlanta reports that employees at the Atlanta facility, which is unioized, said they earn from $50,000 up to $150,000. The head of the unio local that covers the Atlanta plant accused the company of wanting to send jobs to Mexico, but Mondelēz said in its statement that none of the jobs lost by the plant closures will go there.