Scalding is a specific heating technique used to preserve the flavor and quality of breastmilk before long-term storage. This process stabilizes the milk’s components by briefly heating it. Scalding is necessary only for some individuals, but it ensures the milk remains palatable for the baby over time.
Understanding High Lipase Activity
All human milk naturally contains lipase, an enzyme that aids digestion by breaking down milk fats into smaller, easily absorbed molecules. This fat-breakdown process continues even after the milk is expressed and stored.
If milk contains a higher-than-average level of active lipase, the fat breakdown happens quickly. This rapid process causes stored milk to develop a distinct soapy, metallic, or rancid taste and smell. Although the change does not reduce nutritional value, many infants refuse milk with this altered flavor. Scalding deactivates this excess enzyme activity, preserving the milk’s original flavor for long-term storage.
Testing Milk for High Lipase
Before scalding all pumped milk, determine if high lipase activity is causing a flavor change. A simple smell and taste test on a small sample of expressed milk confirms if scalding is necessary.
Store one or two ounces of freshly pumped milk in the refrigerator or freezer. After 24 to 48 hours, thaw the frozen sample or retrieve the refrigerated one, then smell and taste it. If the milk has developed a soapy or metallic flavor, high lipase activity is the likely cause.
If the sample remains fresh-tasting, standard storage is sufficient, and scalding is not required. If the milk develops an off-flavor, determine how quickly this change occurs. Knowing this timeline informs how soon after pumping you must scald the milk.
Step-by-Step Guide to Scalding Milk
Scalding is a heat treatment performed on freshly expressed milk before refrigeration or freezing. The process requires a clean pot and a reliable food thermometer for accuracy. Pour the milk into the pot and place it over medium-low heat.
Gently raise the temperature while stirring constantly to ensure even heating and prevent scorching. Heat the milk to the precise temperature of 180°F (82°C). At this temperature, small bubbles will form around the pot’s inner edge, but the milk should not reach a rolling boil.
This 180°F (82°C) threshold effectively deactivates the lipase enzyme. Heating the milk beyond this point risks degrading beneficial nutrients and antibodies. Once the thermometer confirms 180°F, immediately remove the pot from the heat source to stop the cooking process.
Cooling and Freezing Scalded Milk
Rapid cooling must be performed immediately after scalding to prevent bacterial growth. The quickest method is preparing an ice bath: place the pot or transfer container into a larger bowl filled with ice and cold water. Stir the milk gently in the ice bath until its temperature drops significantly, ideally to refrigerator temperature or below.
Once cooled, transfer the milk into appropriate storage containers, such as specialized freezer bags or bottles. Label each container with the date of scalding and an indication that the milk has been heat-treated. This ensures proper rotation and allows safe storage of the treated milk for an extended period.