Ever wonder how donor milk is pasteurized? Here is a quick synopsis of what happens from the time a donor expresses milk to the time it is distributed for use. Donors express milk at home, using personally owned equipment. They are given instruction on clean techniques for milk expression, including cleaning of pump parts, hand washing, appropriate storage containers, and handling of milk. Milk is stored frozen before delivery to the milk bank. At the bank, frozen milk from several donors is thawed gradually in refrigerators. It is pooled to equilibrate the nutritional content of the milk. Donor milk at the Mothers’ Milk Bank of Montana is pasteurized using the Holder Pasteurization method, in which sealed bottles of pooled milk are heated in a water bath at 62 degrees Celsius and maintained at that temperature for 30 minutes. Milk is then quickly chilled in an ice bath and frozen at -20 degrees Celsius until it is dispensed. A bottle from each batch is sent for bacteriologic testing and the milk bank has to receive a sterile (no bacterial growth) result on the milk before it can be dispensed.