NEW YORK — Shares of consumer packaged foods companies tumbled after General Mills, Inc. announced weaker-than-expected earnings and cut its forecast for fiscal 2018 results.

The General Mills results sent its share price tumbling 9% for the day in trading on the New York Stock Exchange and appeared to have a spillover effect across the food industry. Higher freight costs contributed to the weakness in General Mills shares as well as across the food sector.

Within the Grain-Based Foods Share Index, calculated by Milling & Baking News, numerous companies sustained significant share price declines in March 20 trading — Bridgford Foods Corp., down 3.9%; Campbell Soup Co., down 2.2%; Conagra Brands, Inc., down 2.9%; Flowers Foods, Inc., down 1.6%; Hain Celestial Group, Inc., down 1.7%; Kellogg Co., down 4%; Kraft Heinz Co., down 1.9%; MGP Ingredients, Inc., down 3.7%; Post Holdings, Inc., down 4.2%; and TreeHouse Foods, Inc., down 4.4%.

Overall, the Grain-Based Foods Share Index fell 2% on March 20, versus a 0.1% gain for the S.&P.500 index for the day. Year to date, grain-based shares were down 4.3% through March 20, versus a 2.7% gain for the S.&P. The worst performers to date in 2018 included B&G Foods, Inc., down 22%; Campbell Soup, down 10%; General Mills, off 14%; Hain, down 19%; J&J Snack Foods Corp., down 11%; Kraft, off 16%; and Treehouse Foods, down 17%.