New names continue to grace our annual compilation of the top 100 food companies, which combined to account for $679.4 billion in total sales. Making their first appearance, Constellation Brands, Wm. Wrigley Jr. Co., Pilgrim's Pride and Barilla managed to find a spot on the 2002 list. Many notable absences are not a reflection of poor performance. More likely, it is a result of acquisitions and mergers. IBP Inc. merged into Tyson Foods in September 2001, while Quaker Oats Co. is now in PepsiCo Inc.'s stable and Ralston Purina Co. belongs to Nestle. In addition, Earthgrains now numbers among Sara Lee Corp.'s bakery division, while Suiza Foods and Dean Foods are one and the same under the latter's masthead. Who's left? Read on…