Hello again, I am currently starting to expres...

Hello again, I am currently starting to express milk to freeze for emergencies, etc. Wondering what everyone uses to freeze their milk in. We have limited space in our freezer so some plastic containers, etc are too large once I have a few of them in there (especially when I can only seem to express about 15 mls at a time). I have heard that some people use the snap lock freezer/sandwich bags which I think is a good idea but was wondering about the sterilisation issue... Any thoughts or suggestions? Also, how do you know the expressed milk has enough of the good stuff in it? ie. I had trouble recently where I had too much milk & my little boy was getting too much of the sugary milk rather than the rich creamy stuff....