About 1,400 workers at all of the Kellogg Co.'s US cereal plants went on strike late Tuesday, due to a dispute over benefits and pay that has lasted for more than a year.

The existing contract expired at midnight on Monday. Kellogg plants in Omaha, NE, Battle Creek, MI, Lancaster, PA, and Memphis, TN are included in the work stoppage. 

According to Anthony Shelton, president of Bakery, Confectionery, Tobacco Workers and Grain Millers International Union, Kellogg has demanded that workers give up quality health care, retirement benefits, and holiday and vacation pay. The company has been threatening to send jobs to Mexico if workers do not accept its proposals.

"We are disappointed by the union's decision to strike. Kellogg provides compensation and benefits for our US ready-to-eat cereal employees that are among the industry's best," said Kellogg spokesperson Kris Bahner in a statement.

Kellogg is working on contingency plans to limit supply disruptions for its consumers.