Montgomery County government blue-collar workers, who turned down union representation several years ago, have voted overwhelmingly to join the United Food and Commercial Workers. The union already represents 2,000 white-collar county employes.

In a vote Wednesday, which covered 1,300 workers and was supervised by the state Labor Department, UFCW Local 400 received 661 votes, while 187 voted against union representation and 22 voted for the American Federation of State, County, and Municipal Employees.

"We are very pleased, because we have been working toward getting collective bargaining for some time," said Thomas McNutt, president of Local 400, which has more than 30,000 members, most of them in food and department stores. The union, the largest in the Washington area, had lobbied for the 1984 county referendum in which voters authorized the County Council to develop a collective bargaining law.

McNutt said the union hopes that the council will pass a bill next year authorizing full bargaining rights. Currently, the union can "meet and confer" with county officials about terms of employment, but does not bargain for employes wages and benefits.

The Montgomery County Government Employees Organization, which represented clerical, technical, medical and library workers, merged with UFCW last year, and with this week's vote, they are joined by blue-collar employes including Ride-On bus drivers, mechanics, county liquor store employes, crossing guards and parking meter attendants.