The Senate Foreign Relations Committee, which voted Tuesday to permit food and medical shipments to Cuba for the first time in 17 years, yesterday voted to give the President authority to halt the shipments at any time.

Sen. Jacob K. Javits, (R-N.Y.) proposed an amendment that would explicity state the President's authority to determine when the shipments could be sent to Cuba and when they should be cut off.

But after discussion with Sen. George McGovern (D-S.D.), the panel decided to modify the Javits proposal and merely restate existing presidential authority to roll down the embargo.

A Foreign Service officer gave the State Department reaction: "Our original concern was about two-way trade. We have discussed this with the National Security Council. One-way trade is acceptable, and your amendment makes it all the more acceptable."

The move by Javits, one of the first congressional visitors to the island in 1974, was a further effort to bolster the American bargaining position in subsequent U.S.-Cuban talks aimed at bettering mutual relations.

The Cuba angle was just part of the continuing markup on the $742 million State Department authorization bill for fiscal 1978.

The panel Tuesday approved the future export of food and medicines to Cuba by a 10-to-6 vote, and observers said the provision stood a good chance to make it through final passage by Congress.

Culver Gleysteen, a Foreign Service officer who recently participated in U.S.-Cuban fishing talks, indicated that the State Department could live with the decision.

He told reporters the department had been principally concerned about the premature opening of the U.S. market to Cuban exports.

But Gleysteen said he did not believe Cuba has sufficient foreign exchange to make wide purchases in the United States.