For related articles and more information, please visit OCA’s All About Organics page, Food Safety Research Center page and our Genetic Engineering page.

Renee Shutters has long worried that food dyes – used in candy like blue M&M’s – were hurting her son, Trenton.

She testified before the Food and Drug Administration, but nothing happened. It wasn’t until she went online, using a petition with the help of the Center for Science in the Public Interest, that her pleas to remove artificial dyes from food seemed to be heard.

Mars, the candy’s maker, is now hinting that it may soon replace at least one of the dyes with an alternative derived from seaweed.

“I’ve really thought about calling them,” Ms. Shutters said about Mars. “I’m not trying to be this horrible person. What I’m really thinking is that this is an opportunity for their company to lead what would be an awesome publicity coup by taking these dyes out of their products.”

While the F.D.A. continues to allow certain dyes to be used in foods, deeming them safe, parents and advocacy groups have been using websites and social media as powerful megaphones to force titans of the food industry to reconsider the ingredients in their foods and the labeling and processing of their products. In several instances in the last year or so, major food companies and fast-food chains have shifted to coloring derived from spices or other plant-based sources, or changed or omitted certain labels from packaging.

Matthew Egol, a partner at Booz & Company, the consulting firm, said that while food companies had benefited from social media to gain rapid insight into trends, data on what products to introduce and which words to use in marketing, they also had been the target of complaints that sometimes become magnified in an online environment.

Mr. Egol said companies were approaching the negative feedback they get with new tools that help them assess the risks posed by consumer criticism. “Instead of relying on a P.R. firm, you have analytical tools to quantify how big an issue it is and how rapidly it’s spreading and how influential the people hollering are,” he said. “Then you can make a decision about how to respond. It happens much more quickly.”