Because your baby’s system is very delicate, caution should be used when handling and preparing bottles of both breast milk and formula for your baby. Cleanliness and attention to temperature are vitally important steps in feeding your baby a safe, healthy bottle.
Handling Breast Milk
When pumping breast milk, be sure to wash everything thoroughly, including your hands before handling pump parts and bottles. Pumped breast milk can be left out at room temperature for some time, from four hours to up to 8 hours. Fresh breast milk contains the highest level of nutrition, as some compounds can be damaged by cold temperatures. If your baby will be feeding soon, it’s best to leave it out. If you aren’t planning to use pumped breast milk soon however, you should get it into the fridge immediately, or freeze it for later use. Breast milk can be kept in the fridge for up to 5 days.
While it’s normal to shake up a bottle of formula to dissolve powder into water, you should never shake breast milk. Shaking can damage the delicate molecules and affect the composition of breast milk. You will notice that the fat separates and sits on top of the milk when it is refrigerated. This is normal. The best way to recombine the fat into the milk is to wait until the milk is warmed and then gently swirl it around. This will provide enough agitation to get the fat back into the milk without damaging it.
Once you have thawed breast milk that has been frozen, you should not refreeze it. Frozen breast milk is good for about 3 months in the freezer section of your fridge, and 6 months in a deep freezer.
Formula is a little different from breast milk. As long as it remains unmixed, powdered formula is good for quite a while. Check the expiration date on the can to know how long it will be ok unopened – an open can is good for about a month. Once mixed, however, formula has a shorter shelf life. A bottle of mixed formula should not be left out at room temperature for longer than an hour, and should be discarded after 48 hours in the fridge.
Always mix formula according to the manufacturers directions. Formula should not be diluted with extra water. The best choice for mixing formula is water that has been boiled and then cooled.
Tips for Bottle Feeding
Whether the bottle contains formula or breast milk, you should always discard what is left in the bottle after feeding. Bacteria can get into the bottle from baby’s mouth and cause the leftover liquid to go bad, so don’t save it for a later feeding.
Bottles should be warmed carefully using a bottle warmer or warm water. Never microwave a bottle as it can create dangerous hot spots in the liquid and lead to burns. Microwaving breast milk can also damage its composition. Don’t forget to test the temperature of the liquid inside the bottle – feeling the outside of the bottle is not an accurate measure of how hot the breast milk or formula inside might be.
Make sure that the bottles and nipples are clean and sterile before adding the breast milk or formula, and wash everything in clean soapy water after use. If you dump the leftovers immediately after a feeding, the likelihood of it being fed to baby by accident will be lessened. Also, you can wash the bottle immediately before the contents can start to go bad.