A 70-year-old maitre d' at a Washington restaurant is being sought on a federal warrant that accuses him of bilking his wife, several acquaintances and his boss of more than $120,000 in a scheme involving a phony food salvage business, according to the FBI.

According to an affidavit, submitted yesterday by the FBI, Frank Oshry is accused of transporting money across state lines that he had obtained by fraud. In the affidavit, Oshry's wife, Sue Riley-Oshry, is quoted by the FBI as saying that her husband told her that he was the exclusive food salvaging agent for the Santa Fe Railroad.

She told FBI agents that she contacted the railroad and was told that it had never heard of Frank Oshry, according to the affidavit.

According to the FBI, Oshry said that he purchased food that the railroad couldn't sell because the packaging had been damaged and then sold the food to institutions, such as prisons, for a 50 percent profit. Shortly after the couple's marriage in September, Mrs. Oshry was quoted in the affidavit, her husband began to ask her for money to help operate the business.

She told agents that late last year, Oshry persuaded her to refinance the house the couple lived in at 3127-2 University Boulevard West in Kensington. She told investigators that she gave Oshry $35,000 that he promised to place in their joint checking account and said that he promised to make the new monthly mortgage payments.

Mrs. Oshry told the FBI that between March and May, she gave her husband another $19,434 after withdrawing her savings, cashing her certificates of deposit and her life insurance policy and taking out two loans.

Meanwhile, according to the affidavit, at least a half dozen other people gave Oshry $177,700 to invest in his salvage food business. One of the investors, according to the affidavit, was Tom Mansfield, manager of Quigley's restaurant at 3201 New Mexico Ave. NW, where Oshry worked.

The FBI said Oshry is alleged to have repaid some investors with new investment money. According to the affidavit, Joe Siervo, owner and operator of International Jewelers, 1776 G St. NW, turned over $101,200 to Oshry between March 30 and May 11 of this year, and got $57,300 back.

Mansfield told the FBI that he lost $2,200 after giving Oshry $11,500.

After she had given him a total of $54,656 since December, Mrs. Oshry said in the affidavit, her husband told her on May 11 that he was going to Baltimore on business and that he would return that evening. She told the FBI she has not seen him since.

The FBI said Oshry has a history of arrests dating to 1939. In 1975, he was sentenced to seven years in prison in a fraudulent salvage food operation.

The FBI said Oshry was paroled from the federal prison at Eglin Air Force Base, Fla., in December 1978.