In the past food coloring was a bit dangerous, there were a few cases of addictions in the last few centuries. In 1906 the United States Food and Drugrestricted synthetic food colors to those that could be tested as safe. Since the 1970s the inclusion of colorants in food has received considerable scrutiny based primarily on concerns regarding the carcinogenic properties of colorants. Today manufacturers have moved toward more natural and less synthetic colorants in food.
so I really think its safe to give your family Quaker squares dry cereals.