THE DROUGHT-STRICKEN CENTRAL COAST WILL SOON BE RECEIVING EMERGENCY FOOD AID.   SINCE EMERGENCY DROUGHT RELIEF LEGISLATION PASSED LAST MONTH, THE CALIFORNIA DEPARTMENT OF SOCIAL SERVICES HAS BEEN GATHERING SHIPMENTS OF FOOD.    FOOD ASSISTANCE WILL BE AVAILABLE FOR MONTEREY, SANTA CRUZ, AND SAN BENITO COUNTIES AT LOCAL FOOD BANKS BEGINNING IN EARLY MAY.