International Multifoods Corp. (NYSE:IMC) yesterday reported a 16-percent increase in diluted earnings per share before unusual items for its third quarter ended Nov. 25. Net earnings before unusual items were $9.4 million, or 50 cents per diluted share, compared with $8.1 million, or 43 cents per share, in the prior year. Net sales were $649.8 million, up 3 percent from $632.2 million in the year-earlier quarter. Excluding unusual items, operating earnings rose 19 percent to $19.2 million, up from $16.2 million a year ago.