The film "mission Nutrition" had been running for several minutes when some members of the audience - a seventh-grade class at Montgomery County's parkland Junior High School - began laughing and taunting one of their classmates, according to a suit filed in the county Circuit Court.

What prompted the outburst last December, according to the suit, was the appearance in the film of the student's mother shopping at the local Giant Food store as the narrator intoned: "Some of our chubby friends seems to take in more than they burn up," or, the suit maintains, "similar disparaging nature."

The movie has now been withdrawn from showing by the school system, and details of the film - including what the narrator said - are in dispute.

The suit, filed by Beverly Kouzel of 14200 Chadwick La., Rockville, contends that she was filmed without her knowledge and that she showing of the film caused her "to become an object of ridieule and to suffer emotional distress, humiliation and embarrassment . . ."

Arguing that the film invaded her privacy, Mrs. Kouzel is seeking $700,000 in damages from Astra Films of Washington, which produced the film; Paul L. Brand and Son Inc. of Falls Church, which distributed it, the county school system and Giant Food.

Leonard Grossman, owner of Astra Films, yesterday disputed the contentions made in the suit, saying that everyone who appeared in the film - made seven years ago - had been made aware that they had been filmed.

He said the cameramen were instructed to have everyone who appeared in the film sign a statement acknowleding they knew they had been filmed.

Brand said that as distributor he was not responsible for content.

The school system's attorney said he has not yet drafted an answer to the suit. But a school spokesman characterized its position as being that of "an innocent bystander" and said school oficials, who buy 1,500 films a year, said they had not seen the film in question.

A reporter's effort to reach an attorney for Giant Food was unsuccessful.

According to the spokesman, two prints of the film were purchased from the Brand Co. for $300 in February, 1973. After Mrs. Kouzel called school officials Dec. 31, both prints were withdrawn from circulation, the spokesman said.

Mrs. Kouzel declined to comment when called by a reporter. According to court documents, the 7-year-old film shows her weighing about 100 pounds more than she actually weighed last December.

Her attorney, William F. Abell, disputed the assertions of school officials. He said the officials were "well aware" that the film was made at the Aspen Hill Giant Food Store.

"Our contention is they've got to get permission for this sort of thing" Abell said. "It's not like she was just there in a general crowd of people. She's fully recognizable by anyone who knows her. None of the others in the film are used that way. She's singled out."

Grossman of Astra Films said his company primarily makes films for candidates for political office and that the nutrition film was a "speculative venture. It was not selling, and Astra stopped trying to market it several years ago, he said.

As as far he can remember, Grossman said, the film contains no disparaging statements about overweight people. "Our intention was to do a film on nutrition," he said. "There was not intention to hurt anybody."

He said the suit "will effectively put us out of business whether we win or not. We've been found guilty just by the accusation. No political candidate will touch us now."