Dairy workers and their supporters protested outside Hannaford’s corporate headquarters in Scarborough on Friday, part of a long-running campaign to get the supermarket chain to require that its suppliers adhere to stronger labor protections.

The protest was organized by Migrant Justice, a Vermont-based farmworker rights organization, and drew about 100 people.

For years, the group has been asking Hannaford, and other food retailers, to join its Milk with Dignity program.

The program requires companies pay a premium on dairy products to ensure that workers in the supply chain have adequate housing, paid sick days and other protections.

Speaking in Spanish, dairy worker Jose Ignacio said he still has hope that Hannaford will agree to the program, because when farmworkers come to together, he said, their demands must be heard.