Nicholas G. Kontos, 80, who owned and operated the Purity Food Shop in Washington for more than 30 years, died of congestive heart failure Saturday at his home in Vienna.

Mr. Kontos founded the Purity Food Shop, a breakfast and lunch carry-out restaurant and tavern, shortly after World War II. The shop was in the basement of the old Adas Temple Shrine on Sixth Street NW, until moving to 601 F Street NW in 1968.

Mr. Kontos had been in semi-retirement for reasons of health for the past year while his son, Charles N. Kontos of Washington, managed the store.

Nicholas Kontos was born on a Greek island in the Aegean Sea and sailed the Atlantic with the Greek merchant marine before coming to this country in the late 1920s.

He was a member of the U.S. Merchant Marine on the Great Lakes before coming to Washington in the early 1940s. He was an engineer at the Navy torpedo factory in Alexandria during World War II.

He was a member of the Saint Sophia Greek Orthodox Cathedral community for more than 30 years and had served as an officer of the American Hellenic Education Progressive Association (AHEPA) and belonged to the association for more than 35 years.

In adition to his som, Mr. Kontos is survived by his wife of 37 years, the former Pauline Eliades of Vienna; a daughter, Evanphia Ann Marmaras of Chevy Chase; two brothers, Demetrious and Anthony Constaninos Kalogrides, and a sister, Maria Strates, all of Greece.

The family suggest that expressions of sympathy be in the form of contributions to the Saint Sophia Greek Orthodox Cathedral.