FREE MOVEMENT OF GOODS - EXCEPTIONS - PROTECTION OF PUBLIC HEALTH - RULES REGULATING THE PRESENCE IN FOODSTUFFS OF RESIDUES OF PESTICIDES NOT COVERED BY THE PROVISIONS OF COMMUNITY LAW - POWERS OF THE MEMBER STATES - PROHIBITION ON THE MARKETING OF FRUIT AND VEGETABLES TREATED WITH MALEIC HYDRAZIDE - PERMISSIBILITY ( EEC TREATY , ARTS 30 AND 36 )