(Protesters outside the Home Depot in Richfield on Tuesday. Photo by Adam Belz)

Janitors who work for companies that clean Home Depot, Best Buy, Kohl's and Sears stores are setting a Black Friday deadline for a strike unless the cleaning companies negotiate with workers trying to organize a bargaining unit under the Service Employees International Union (SEIU).

Several dozen supporters and four workers who are members of the worker center CTUL held a protest in the snow and cold near the Home Depot in Richfield just off Highway 77 and 66th Street on Tuesday.

Only four working janitors made Tuesday's protest, but CTUL says "dozens" of workers are ready to strike on Black Friday if their demands aren't met, and released a video of some of them saying as much. Low wages are among the workers' grievances.

"The wages that we make are so low, we can't survive on these wages," said Luciano Balbuena, a janitor, as the wind whipped through the gathering just north of the Home Depot.

On Tuesday, the janitors were joined by several dozen health workers from the National Association of City and County Health Officials.

Janitors in the Twin Cities and CTUL won a victory in June 2014, when Target Corp. created a "Responsible Contractor Policy" that requires companies contracted to clean Target stores to engage with workers to improve working standards in the industry. CTUL had protested Target several times.

Many other retailers haven't adopted a similar policy, however, and CTUL said in a statement that the company's Target pays for cleaning services "have not seemed to take workers’ concerns seriously." Other cleaning companies have refused to talk with the workers, CTUL said.

The protest on Tuesday will be against both large retailers who don't have a policy similar to Target's, and against cleaning contractors.

CTUL (pronounced SAY-tool) stands for Centro de Trabajadores Unidos en la Lucha, and is a workers' association that works closely with the SEIU. CTUL has been organizing retail janitors for four years.

Worker centers like CTUL have begun to irk some businesses because of their resemblance to organized labor. But the National Labor Relations Board concluded in 2006 that one large worker center, the Restaurant Opportunities Center, was not a union.

Updated throughout.