Commission Regulation (EEC) No 2675/91 of 9 September 1991 correcting Regulation (EEC) No 1157/91 amending Regulation (EEC) No 570/88 on the sale of butter at reduced prices and the granting of aid for butter and concentrated butter for use in the manufacture of pastry products, ice-cream and other foodstuffs and amending Regulation (EEC) No 569/88