I spoke to an ABA counsellor about this and apparently it is fine. If you don't have EBM bags (you can buy them at chemists etc) then this is the next best option..... when you think about it, nothing is sterile once it's been opened yeah? Even an EBM bag designed for storing breastmilk in it, once that is opened and exposed to air, then nope it's not sterile anymore..... so yeah I think this would be okay. I have spoken to lots of mum's who have done this.

Remember breastmilk has antibacterial properties in it

I'm thinking about buying some ice cube trays with lids especially for my EBM when bub arrives.