Research has shown that breast milk can help lower the risk of infection in premature infants because of certain naturally-occuring antimicrobial proteins present in the breast milk.  Some commercially available fortifiers contain more or less amounts of iron than others.  It is thought that the presence of iron in fortified breast milk may affect how the antimicrobial proteins work.  One of the aims of this research study is to evaluate whether the addition of iron to fortified breast milk will affect the rate of bacterial growth when the breast milk is stored for an extended period of time.

The second aim of this research is to evaluate the affect of pasteurization (high heat applied to kill bacteria) on breast milk.  Not all mothers of premature infants are able to produce sufficient quantities of milk for their infants during their hospital stay. As a result, there has been an increase in the use of pasteurized donor breast milk in hospitalized premature infants. 

The third aim of this research is to evaluate the effects of refrigeration of fresh breast milk on bacterial growth and proteins and nutrients when breast milk is stored for an extended period of time.

This research study is designed to:

1. compare the effects of adding two different human milk fortifiers (Enfamil and Similac) on bacterial growth in breast milk
2. evaluate the effects of pasteurization on the proteins and nutrients in natural breast milk
3. evaluate the effects of refrigeration and storage time on bacterial growth and proteins and nutrients in breast milk.