Within a raft of trading updates this week, Kellogg and Chiquita Brands International posted disappointing results, although Unilever and organics retailer Whole Foods Market had better news for the market. Heinz is entering what may become a protracted series of negotations with its Wigan staff over wages, while rumours abound that Marks and Spencer may look to re-acquire the stores in western Europe that it sold in 2001. Here's the best of what was said this week.