1 . COMMUNITY LAW - GENERAL PRINCIPLES - PROPORTIONALITY - PROPORTIONAL NATURE OF A MEASURE - CRITERIA FOR ASSESSMENT 2 . AGRICULTURE - COMMON ORGANIZATION OF THE MARKETS - MILK AND MILK PRODUCTS - BUTTER OFFERED FOR SALE AT A REDUCED PRICE - COMPULSORY PROCESSING OF BUTTER WITHIN A SPECIFIED PERIOD - PROVISION OF SECURITY BY THE SUCCESSFUL TENDERER - FAILURE TO OBSERVE THE PROCESSING PERIOD - TOTAL FORFEITURE OF THE SECURITY - PRINCIPLE OF PROPORTIONALITY - BREACH - NONE ( REGULATIONS ( EEC ) OF THE COMMISSION NOS 1259/72 , ART . 18 ( 2 ) AND 232/75 , ARTS 18 ( 2 ) AND 19 )