Carcinogenicity and regulation of caramel colorings

Int J Occup Environ Health. 2012 Jul-Sep;18(3):254-9. doi: 10.1179/1077352512Z.00000000031.


2- and 4-methylimidazoles are present as contaminants in caramel colorings manufactured with ammonia catalysts. Both contaminants have been shown to induce cancer in animals and may be present in caramel colorings in amounts that exceed federal guidelines. California requires warning notices on products that could lead to consumption of more than 30 micrograms per day. The US Food and Drug Administration should bar the use of excessively contaminated caramel coloring in food.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • California
  • Candy / toxicity*
  • Carbohydrates
  • Carcinogens / chemical synthesis
  • Carcinogens / toxicity*
  • Food Coloring Agents / chemical synthesis
  • Food Coloring Agents / toxicity*
  • Imidazoles / chemical synthesis
  • Imidazoles / toxicity
  • Legislation, Food*
  • United States
  • United States Food and Drug Administration


  • Carbohydrates
  • Carcinogens
  • Food Coloring Agents
  • Imidazoles
  • caramel coloring
  • 4-methylimidazole
  • 2-methylimidazole