|Infant formulas are available in many different forms, including those that are ready to feed, which comes in 32oz cans and requires no preparation. Once opened, ready to feed formula must be refrigerated and used with forty eight hours. Ready to feed formulas are usually the most expensive.
Formula can also be concentrated in 13 oz cans, and require dilution with water on a 1:1 basis (one ounce of water for one ounce of concentrated formula). Powder formulas are prepared by mixing one scoop of formula with two ounces of water. Powder formulas are usually the least expensive. When comparing formula prices, check to see how much formula the can makes, since many cans that look like they are the same size do not make the same amount of formula.
If you live in a city with sanitized water and you are preparing bottles one at a time, then boiling water or sterilizing the bottles and nipples isn't necessary. You may be able to use this water out of the tap and bottles can be washed in hot soapy water or in the dishwasher. If you are not convinced that your water supply is safe or if you are using well water, then you should boil the water for five minutes before preparing formula.
Boiling the water when preparing infant formula was universally recommended and was then thought to be unnessesary. In 1993, an outbreak of cyclosporiasis from contaminated water in Milwaukee prompted officials to again recommend that water be boiled when preparing infant formula. However, the American Academy of Pediatrics does recommend that water that is going to be used for infant formula be boiled. If you don't want to boil the water first, you could use 'sterile' bottled water instead. Bottled water that isn't marked sterile should probably still be boiled.
You should discard any formula in the bottle that is not finished during the feeding.
Your baby may accept formula prepared with cold water, or he may prefer to have the formula warmed. You may warm formula by briefly placing it under hot running water, using a bottle warmer or on the stove. Do not warm formula in the microwave, as it can produce hot spots in the bottle that can burn your baby. And always test warmed formula before feeding it to your baby.
If you are using ready to feed formula or are preparing concentrated or powder formulas with bottled or filtered water, then you may need to give your baby fluoride supplements when he is older. Check with your doctor.