Infant formula is a modern artificial substitute for human breast milk. Formulas are designed for infant consumption, and are usually based on either cow milk or soy milk. Use of infant formula has been decreasing in industrial countries for over forty years as a result of antenatal education, increased understanding of the risks of infant formula, and social activism. Most major medical and health organizations strongly advocate breastfeeding over the use of infant formula.

Besides breast milk, infant formula is the only other infant milk which the medical community considers nutritionally acceptable for infants under the age of one year. Cow's milk is not recommended because of its high protein and electrolyte (salt) content which may put a strain on an infant's immature kidneys. Evaporated milk, although perhaps easier to digest due to the processing of the protein, is still nutritionally inadequate.

Infant formula is available in powder, liquid concentrate and ready-to-feed forms, which are prepared by the caregiver or parent in small batches and fed to the infant, usually with either a baby bottle or cup. It is very important to measure powders or concentrates accurately to achieve the intended final product. It is advisable that all equipment that comes into contact with the infant formula be cleaned and sterilized before each use. Proper refrigeration is essential for any infant formula which is prepared in advance, since infant formula is especially susceptible to bacterial growth. Powdered, cow's milk-based infant formulas are not recommended for premature or sick infants, or for infants under one month of age. Powdered infant formulas are not sterile and may be contaminated with Enterobacter sakazakii, bacteria that may lead to neonatal meningitis, sepsis and necrotizing entercolitis in infants with weak or compromised immune systems.

Source: wikipedia GFDL