Let me start by saying a chemical additive doesn't necessarily 'appear' to be a problem immediately after ingestion. Quite often the effects are cumulative; a gradual build-up in the body produces roller-coaster days, some good, some bad. Some children are more sensitive to food chemicals and display immediate effects soon after ingestion of additives, colours in particular. In small amounts additives are not harmful. Effects are dose related and, tragically, dose for weight, children are consuming several times more additives than the acceptable daily intake (ADI). Before we get into the details of the most common problem foods, it is necessary to understand the testing and approval process, with emphasis on those factors that may confer the level of risk of toxic additives in infants and young children's diets.