Adding freshly expressed milk to milk already in fridge

[JuniorMint]

I have just read online that to avoid wasting expressed milk, you can keep adding expressed milk into one container in the fridge then just putting a smaller amount into baby's bottle as needed. Can anyone offer any advice on the safest and easiest way to do this- what kind of container? Would I just keep one bottle in the fridge then each time I express, pour it from the bottle on the steriliser into the bottle in the fridge, then when I want to use some measure it out into a freshly expressed bottle? Would I need to tip away and sterilise the "fridge bottle" with some degree of regularity, as the age of any one part of the milk in there wouldn't be guaranteed?!

TIA for any advice! DD is only 4 days old and I didn't envisage expressing so soon but we have just come out of hospital due to her low birth weight and she had top up formula feeds there plus EBM (plus being on the breast). I am wanting to cut the formula out now we're home but am beginning to get a good amount now and as I say above, don't want to waste it each time but rather keep in a central container in fridge and measure out amounts needed for each feed.

Thank you!

Ok, if you're adding expressed milk to previously expressed milk, you need to add cold to cold - so if you want to store it all in one bottle/other receptacle, you need to put the freshly expressed milk in the fridge first, wait til its cold, then add it to the previously expressed milk. Any clean/sterile container with a lid would do.

And yes, you couldn't just keep topping up the fridge bottle, the combined milk is basically as fresh as the oldest milk in the bottle in terms of how long you can keep it for. Combining milk from different pumping sessions just means you're not stuck with random quantities and can freeze/use it in 2oz batches, say.

Thank you! That is really useful!