(Reuters) – About 1400 employees of Kellogg’s Co cereal plants went on strike Tuesday in an attempt to force the company to agree to a fair contract for their workers.

For a time, the Corn Flakes and Froot Loops cereal manufacturer have been in negotiations with union workers regarding their pay and benefits.

Anthony Shelton, the president of Bakery, Confectionery, Tobacco Workers and Grain Millers International Union, released a statement saying that the company had demanded that employees give up quality healthcare, retirement benefits, and vacation and holiday pay.

Shelton stated that Kellogg had threatened to send further jobs to Mexico to workers who refuse its proposal.

Union members went on strike at factories in Battle Creek (Michigan), Omaha, Nebraska; Lancaster, Pennsylvania, and Memphis, Tennessee.

Kellogg claims it does provide compensation and benefits for U.S. ready to eat cereal workers who are the most skilled in the sector.

Kris Bahner, spokesperson for Kellogg said that “We are disappointed at the union’s decision not to strike… Our offer includes increases in pay and benefits to our employees.”

Kellogg indicated that it is open to continuing negotiations in order to come to an agreement, and was working on contingency plans to address supply disruptions including those involving third-party resources.