Food conglomerate ConAgra Inc. said it's buying International Home Foods Inc., the maker of Chef Boyardee pasta products, Pam cooking spray and Gulden's Mustard, for $1.6 billion in cash and stock. The deal comes amid a flurry of consolidation in the food industry as manufacturers seek to expand their portfolios of brands so they can have more clout with grocers in bargaining for shelf space. Omaha-based ConAgra has annual sales of more than $25 billion and owns companies across the food chain, including meatpacking and fertilizer businesses and about 100 consumer brands, including such well-known names as Butterball, Healthy Choice, Orville Redenbacher and Swiss Miss. International Home Foods, based in Parsippany, N.J., was formed in November 1996 when a group of investors acquired the food business of Madison, N.J.-based American Home Products. Under the deal, International Home Foods shareholders will receive $22 a share, half in cash and half in ConAgra stock. International Home shares jumped $5.25 to close at $20.63 on the New York Stock Exchange. As part of the deal, ConAgra will also assume $1.3 billion of debt.