A German sporting goods manufacturer and an Italian heavy equipment producer announced yesterday that they will move their American operations to the 77-acre foreign trade zone in the Collington Center industrial park near Bowie, bringing to seven the number of firms attracted to the site by state and federal incentives.

Mistral Inc. of Germany and the Italian-owned Benati USA Inc. together will employ more than 60 persons, about half of whom will be hired for newly created jobs, company officials said. Mistral also will be seeking a $2.4 million industrial revenue bond from Prince George's County, a company spokesman said.

The congressionally mandated foreign trade zones were set up to allow firms to import and assemble products free of tariffs that would otherwise be imposed.

Joseph D. McMahon, a representative of the Maryland Department of Economic and Community Development, said that state foreign trade officials based in Belgium contacted the companies and persuaded them to move their American headquarters to Collington Center, one of three foreign trade zones in the state. Other zones are at the Port of Baltimore and Baltimore-Washington International Airport.

Mistral, which specializes in board sailing gear, is moving from a site near BWI in Anne Arundel County, where it opened its United States headquarters in 1982. The firm reported $15 million in revenues last year.

The Benati facility will be used for light assembly in the first year, marketing director Anthony Zak said. He said the company opened its first American headquarters in Oklahoma because it was centrally located in the United States, but found that it was "far away from everyplace."

Zak said that Benati revenues in the United States totaled $5 million last year, and said he expects business to grow by a third each year for the next several years.

County Executive Parris Glendening hailed yesterday's announcement as an indication that the foreign trade center, near Rtes. 301 and 214, is a success