Yes ofcourse you can. One can preserve BM in room temperature upto 6 hrs if its not too hot, if the weather is too hot then 4 hrs in room temperature. If you are refrigerating the keep it behind it will stay fresh up to 24 hrs, if freezed then no time line. Always taste the BM before offering the baby, if its sour then discard it. Never hear the BM directly on fire, you keep the container in warm water. There are lot of bags available to store the milk however you can simply store it steel containers also.