Two women who blog about food don't want your children to eat what could be one of the few foods they like to eat: Kraft Mac & Cheese. Lisa Leake, a mother who writes at "100 Days of Real Food," and Vani Hari, a management consultant by day who blogs as "Food Babe," have launched a multimedia campaign to try to get Kraft to stop using artificial food coloring — in particular, Yellow 5 and Yellow 6 — in its iconic macaroni and cheese products. They say the dyes might be harmful to kids, have been linked to cancer, have no nutritional value and are banned in other countries, including the United Kingdom. "We think this is an important issue to tackle because Kraft Macaroni & Cheese is an iconic food product. Everyone's had it at one time or another," Leake says on a video she and Hari recorded to go with their "Stop Using Dangerous Food Dyes in Our Mac & Cheese" petition. "I used to eat it. Vani's had it. I used to feed it to my kids years ago, and we think we deserve the same version that our friends overseas in the U.K. get without artificial food dyes," Leake says on the video. Hari says artificial food dyes are made in a laboratory with chemicals derived from petroleum, are outright prohibited in some countries and require a warning label in others. She and Leake say the dyes can cause an increase in hyperactivity in children and impair their ability to learn. Northfield, Ill.-based Kraft Foods Group, one of America's largest consumer packaged food and beverage companies, denied that its Mac & Cheese meals can be harmful. "The safety and quality of our products is our highest priority and we take consumer concerns very seriously. We carefully follow the laws and regulations in the countries where our products are sold. So in the U.S., we only use colors that are approved and deemed safe for food use by the Food and Drug Administration," Kraft spokeswoman Lynne Galia said Thursday in a statement to MSN News. Galia noted that Kraft expanded its Mac & Cheese line to include alternative offerings without artificial food dyes. "We know some people prefer foods without certain ingredients -— we now offer a multitude of products without added colors, as well as products with natural food colors," she said. It was the same statement Kraft issued to Hari and Leake in response to their petition, which by Thursday had drawn more than 40,000 signatures. "We commend Kraft for responding to our petition, but they are missing the bigger issue. Approximately 30 Kraft Macaroni & Cheese products still have dangerous artificial dyes and this is unfair to the children lured by these products (several packages showcase cartoon characters), unfair to the less fortunate who buy these products because they are cheaper, and unfair to the uneducated consumer that is unaware of these harmful ingredients," Hari said in an email statement to MSN News on Thursday. She said the ultimate goal is to get all U.S. food companies to eliminate the use of artificial food dyes. In their video, Leake and Hari do a taste test by sampling from two plates of Kraft macaroni and cheese — one made from the U.S. version and one made from the U.K. version. "I think they taste virtually the same," Leake concludes after a couple of forkfuls. It's not the first time activists have tried to persuade food-products companies and the federal government to ban the use of artificial coloring in foods. The consumer advocacy group Center for Science in the Public Interest has for years been lobbying the FDA to ban the use of food dyes, citing a "rainbow of risks" that it says includes hyperactivity in children, allergic reactions and a possible link to cancer. An FDA advisory panel held hearings in 2011 and decided against a ban. The panel concluded that existing evidence between dyes and attention deficit hyperactivity disorder is weak and more research is needed. Yellow Nos. 5 and 6 are among nine color additives approved for use in the U.S. "Without color additives, colas wouldn't be brown, margarine wouldn't be yellow and mint ice cream wouldn't be green. Color additives are now recognized as an important part of practically all processed foods we eat," the FDA says on its website.