Chairman Jesse Helms (R-N.C.) of the Senate Agriculture Committee said yesterday that food exports "probably will be out main foreign policy lever" in protecting U.S. interests abroad in the future.

". . . It ought to be used in terms of leverage," Helms said of American agricultural power in an interview on "Meet the Press" (NBC, WRC).

"We're entering an era when we're no longer going to be talking about surpluses of agriculture products, we're going to be talking about shortages" on an international level, Helms said. "Surely, that is bound to have an impact on how much and to whom and with whom we share the remarkable ability of the American farmers to produce."

Helms also spoke of setting up an economic blocade against Cuba, or "doing whatever is required" to stem the alleged flow of arms from that Caribbean nation to opposition forces in El Salvador, saying, "We're talking about our back yard."

He said the United States must do "whatever is necessary to draw the line [against communist expansion] because, when you stop and think about it, if we don't draw the line south of El Salvador in 1981 we may have to draw it north of Mexico . . . "

Helms also said the Reagan administration has cut off U.S. aid to Nicaragua because of its alleged role in the relay of arms to Salvadoran guerrillas. The State Department reiterated yesterday that aid to Nicaragua "has been suspended."

Helms said that "drawing the line" does not necessarily mean sending U.S. troops to El Salvador, and that he supports the concept of a "hemispheric council" to deal with such threats.