Infant formulas are liquids or reconstituted powders fed to infants and young children to serve as substitutes for human milk. Infant formulas have a special role in the diet because they are the only source of nutrients for some infants and many receive infant formula at some time during their first year of life, often in combination with breastfeeding.

Although existing federal guidelines and regulations for evaluating the safety of food ingredients have worked well for conventional substances (e.g., vitamins, minerals), they are not sufficient to address the diversity of potential new ingredients proposed by manufacturers to develop formulas that mimic human milk, says a report from the IOM. In the report, the committee provides guidelines that clarify the types and extent of safety testing necessary for new formula ingredients, particularly unconventional substances derived from novel sources or technologies. To help formula manufacturers and their outside expert reviewers determine what safety data are needed on a proposed ingredient and how they should be gathered, the report also offers a set of "decision trees" -- hierarchical series of questions leading to specific action steps -- to guide the level and extent of safety testing needed at various stages.