It's time to stuff yourself with good Greek food again. The annual spate of Greek church festivals and bazaars continues tomorrow on the grounds of Six Constantine and Helen Greek Orthodox Church, 4115 16th St. NW.

If you get there early enough you might not have to stand in line to eat moussaka, dolmades (stuffed grape leaves), spinach pies, pastitsio, sousoukakia (meat balls), souvlakia (Meat on a skewer), spit roasted lamb, not to mention the sweets like baklava and kouramblades (Butter cookies).

If you don't want to eat your lunch or dinner there, you can buy these things to take home.

The festival will open Friday at noon and close at 10 p.m.; Saturday from noon to 9 p.m. and Sunday from noon to 10 p.m. There is no admission charge.

If you've always wanted to own a $135-jar of black French truffles, but never wanted to lay out the money for it, you can win one instead.

To celebrate its 40th anniversary in the Spring Valley Shopping Center on Massachusetts Avenue, Wagshal's Delicatessan is offering three seven-ounce jars of truffles, each worth $135.All you have to do is fill out a form each time you go into Wagshal's between now and Sept. 22, when WRC-TV weatherman Willard Scott will pick the three winners.

You don't have to buy anything to enter and you don't have to be present to win.

The Department of Agriculture has ordered Briggs and Co., the Washington-based division of Wilson Foods Corp., to stop using, "unfair and discriminatory pricing practices in the sale of processed meats."

Wilson has been charged with selling Briggs' products to favored retailers and wholesalers at prices as much as 18 cents per pound lower than prices charged to competing retailers and wholesalers.

The firm, one of the nation's largest meat packers, consented to the order following hearings in Washington.

If you want to have your say about what should be on food labels, either present yourself at the HEW Auditorium on September 27 and sign up, or call the Food and Drug Administration in advance.

Starting at 9:30 a.m. on the 27th, FDA Commissioner, Dr. Donald Kennedy, along with representatives from the Department of Agriculture and the Federal Trade Commission will preside at the third in a series of five hearings being held around the country to find out what people think should be on food labels.

The three agencies, which share responsibility for regulating food labeling and promotion, want to know what kind of information should be on food labels; how ingredients should be listed; what the best way is to present nutrition information; whether or not there should be some form of open dating.

The agencies have a booklet available which describes some of these issues. You can get a copy by calling 557-0389. That's the same number of call if you want to signup in advance to testify.

Otherwise, you can plan to spend all of September 27, into the evening, and possibly Sept. 28 at the HEW Auditorium, 330 Independence Ave.

$25,000 for your favorite canned pineapple recipe - if the judges of the National Pineapple Cooking Classic agree that yours is the best.

Even if you don't win top prize, if you get into the finals you get an all-expense-paid trip for two to Hawaii for a week next April.

A total of $65,000 in cash prizes will be awarded.

Entry blanks are available either at grocery stores or by writing to: National Pineapple Cooking Classic, 4th floor, 747 Front St., San Francisco, Calif. 94111.