I am having difficulty storing breast milk for my baby. I am a full-time breastfeeding mother at home. When I need to go out for errands and leave her in the house, I make sure I have enough milk stored for her. I usually pump milk every night and store it in the fridge. I use bottle warmers for the milk. I noticed that every time it is left for a couple of hours on a room temperature or when exposed to sunlight, the milk curdles. I know that when milk curdles it means that it is already spoiled. How can it be spoiled when there is no contact with saliva? How long can I store my breast milk without affecting its quality?