Powdered infant formula is NOT a sterile product. This is particularly important for infants at high risk. There are organisms that can be found in powdered infant formula including Salmonella and E. Sakazakii. Not appealing!
What should you do? You should BOIL the water that you use to mix the formula and do not allow it to cool below 158 degrees F before mixing. This hot water kills any bacteria present in the powdered formula.
THEN cool the mixed formula to body temperature BEFORE you feed the infant or immediately store it in the refrigerator.
A clean water source is important and luckily in the United States that is not usually a problem.
Remember, Whether tap, bottled or infant water the boiling of the water is to sterilize the Powdered Infant Formula!
The World Health Organization supports this!