Changes to 91/449/EEC: Commission Decision of 26 July 1991 laying down the specimen animal health certificates in respect of meat products imported from third countries
EU Decision 1991/449
Made by 94/667/EC: Commission Decision of 6 October 1994 concerning the importation into the Community of fresh pigmeat, pigmeat products, live pigs, porcine semen and porcine embryos from Switzerland and amending Decisions 81/526/EEC, 91/449/EEC, 92/460/EEC and 93/199/EEC
From legislation.gov.uk's record of changes, the official one: see it there.