LUXEMBOURG — The European Court of Justice, Europe’s highest court, on July 9 reduced Decatur, Ill.-based Archer Daniels Midland Co.’s fine previously imposed by the European Commission for price-fixing of citric acid to €29.4 million ($41.2 million) from €39.69 million ($55.5 million). In addition, the court ruled that ADM should not have been classified as a leader in the cartel. The Commission fined five producers of citric acid a total of €135.22 million for participating in what it claims was a secret worldwide cartel between 1991 and 1995. In September 2006, the Commission upheld its original ruling from 2001. Citric acid is a widespread preservative used mainly in food such as jams, jellies and tinned fruit.