Could it simply be – Lactation Lab

Lipase in Milk and Taste: Ways to minimize Lipase: Could it simply be a cooling measure?

Human milk contains two different types of lipases: Lipases are essential enzymes that help break down fats and are necessary for digestion. All breast milk contains lipase enzymes. There have been many contradictory recommendations regarding lipase concentration in milk and its relation to the taste of breast-milk. Many folks recommend scalding the breast milk to try to inactivate the lipase concentration. I strongly recommend that you do not do this! Heating human milk at a very high temperature will destroy white blood cells and significantly alter protein so that they’re no longer as effective as they were. To reduce the chance of bad tasting milk, follow stricter milk collection and storage guidelines. I recommend that freshly pumped milk be refrigerated before it is frozen. The slow cooling temperature will help control for, and preserve the number of cells and proteins intact. Never microwave or boil breast milk.

To defrost milk, I recommend that it go from the freezer to the fridge and let sit for 24 hours. It can then be gently warmed using a bottle warmer. 

For women who have milk that is “foul-tasting” whose babies refuse it, we recommend either 

1) mixing it with freshly expressed milk or 2) mixing it in with solid foods once they are introduced. You do not need to throw away milk because of perceived bad taste.