Washington ? Nora Pouillon was called a hippy in the 1970s for buying only organic fruits, vegetables and meats for her family. People scoffed when she went so far as to serve organic-only meals at her Washington restaurant and advertised it on the menu.

“I had written on the back of my menus that the animals were raised in a stress-free environment,” said Pouillon, the chef and owner of the organic-certified Restaurant Nora. “People were making fun of me.”

Pouillon does not feel alone anymore as an organic shopper, and sales of organic food prove it. They have increased steadily, from $3.5 billion in 1996 to $4 billion in 1999. The Agriculture Department has taken notice, writing labeling rules for farmers and companies wanting to market their products as organic. The rules take effect Monday.

The agency also will begin marking some of those foods with a seal of approval.

The seal means the food was grown by a certified farmer who does not use conventional pesticides and fertilizers, biotechnology, antibiotics or growth hormones to produce food.

Products entirely organic will be labeled “100 percent organic” while those that are at least 95 percent will carry just “organic.” The seal can be displayed on those products.

Foods that are 70 percent organic or less will be marked as “made with organic ingredients” or “contains organic ingredients.” Those cannot carry the department’s green seal.

The government is not saying organic foods are safer or healthier. That claim is made by organic supporters.

“I believe that on a political level, consumers can go into the store and vote with their food dollars,” said Kelly Shea, a production director at the California dairy and meat company Horizon Organic. “Both producers and the consumers can have a hand in contributing to better soil quality, better water quality and promoting the humane treatment of animals.”