Is it better to store breast milk in bottles or bags?

See below. If the plastic bags are bpa free they are probably ok. The safest will always be glass bottles that have been sterilized between use.
Either will do well. You can choose your preference bags or bottles as long as they are made especially for storage. My wife used/uses the lansinoh breastmilk storage bags.

Related Questions

What is the best way to store breast milk?

Frozen. In a separate freezer compartment, not a freezer "box" inside a refrigerator. Read more...
In the freezer. It is best early on (when your baby is only drinking 2 or 3 ounces of milk at a feeding) to store the milk in tightly ziplocked breast feeding bags in small amounts. Keep them in the very back of your freezer (not in the door area where the temperature fluctuates frequently) for up to 6 months. As your baby gets older, you can store larger amounts at a time. Read more...

What are the best ways to store breast milk?

Fridge. You can store breast milk in the refrigerator for up to 8 days and in the freezer compartment for up to 2 weeks. If your freezer has a separate door, you can store breast milk for 3-6 months. Be sure to clean containers (plastic or glass) in a dishwasher or wash with hot, soapy water. It's best to fill individual containers with the amount of milk your baby will need for just one feeding. Read more...
See below. Freezing breast milk provides the longest storage. In the refrigerator, i would not store for longer than 24 hours. Read more...

Can I save an unfinished bottle of breast milk for a later feeding?

Yes. Saving it for the next feeding is fine, but check that the milk is not breaking down (if it has small clumps or smells like rancid butter--toss it out). Don't refreeze, and if you haven't used it several hours later, it's likely gone bad. Read more...
See below. If the baby drank out of the bottle, the breast milk should be discarded. Read more...

Are plastic bags for breast milk bad?

Glass is better. Make sure your bags are bpa free. Glass bottles are much less toxic. Read more...

What is the best way to store breast milk I have pumped?

Freeze it! Breast milk should be stored in sterile plastic bags or containers, about 2 oz at a time. It can be frozen and stored for several months. Label the bag with the date. It can also be kept in the refrigerator if it will be used within 48 hours. Remember, when you defrost the milk, do not put it in the microwave! this can cause hot spots and may destroy some of the milks nutrients. Read more...
Fridge or freezer. Breastmilk can be stored in the refrigerator for several days and in the freezer for 3-4 months. The white blood cells in the milk die in the freezer lessening the milk's anti-infective properties slightly so if you're pumping at work for the next day's use, store the milk in sterile bags or bottles in the fridge. But if you're not sure when it will get used it's best to store it in the freezer. Read more...

How often and how many ounces should a 2 week old be eating? I'm giving her breast milk and formula in a bottle.

Great weight is key. A 2 week old will eat often, though each child develops his/her own pattern. For breastfeeding, a 20-30 minute session every 2 hours is typical for an infant this age. With bottle feeding, 2 oz every 2 hours is typical. Try breastfeeding first - often you don't need a bottle then. The best way to know you're baby is getting enough is if they're gaining weight - good weight gain means enough food. Read more...
150 ml/kg/day. Breast milk or formula both have 20 cal/oz. A baby should be eating about 100 cal/kg/day so drink about 150 ml/kg/day. If your child weighs about 3 kg then needs to drink about 450-500 ml a daywhich is about 15-17 oz a day so about 2 oz every 3 hrs. Read more...

Should I be concerned if my six week can't nurse properly she is born 6week earlier I use to bottle feed her (with breast milk)but.?

Lactation specialist. Not sure i understood the question but it sounds like you are having trouble with your infant breast feeding as the infant was born premature. A lactation specialist which they should have in the hospital can give you a great deal of advice. There are many people in the community that the dr could refer you to that might be very glad to help. Read more...