But when lipase activity is excessively high, it breaks down fat too quickly, which can lead to breast milk that tastes or smells soapy or metallic. These changes can be noticeable after your milk has been pumped and stored. Only a small number of women have excess lipase activity in their breast milk.
Be that as it may, the temperature range of typical domestic freezer is generally −18°C to −20°C and human breastmilk frozen storage at home is not usually pasteurized before freezing, and so the rancid-flavor development of breastmilk due to lipolysis is generally inevitable under the typical frozen-storage regime.
Oxidized flavors in milk have been described as tasting like cardboard or metallic taste. If this off-flavor is detected, a water test may be needed to check for minerals, including copper, iron, and sulfur.
Freezing will not prevent lipase activity from altering the aroma or taste of your milk, but scalding will.
IS IT DANGEROUS FOR MY BABY TO DRINK HIGH LIPASE MILK? NO! The milk is still perfectly fine for them to drink! Many babies, however, will not drink the milk because of the smell and taste.
Here are three reasons why your baby may be rejecting your precious breast milk: Things may not be squeaky clean. Excess Lipase lurking around. Chemical oxidation (it's not as serious as it sounds)
Some babies don't mind the taste, while others will refuse to drink the defrosted breastmilk (like mine)! If your baby is rejecting your soapy smelling breastmilk, you can try scalding it right before freezing it. This helps to decrease the lipase in the breastmilk stopping it from breaking down the fats.
Breast milk is sometimes described as tasting soapy or a little sour. It can smell or taste of something the mother has eaten recently as some foods can flavour breast milk. Sometimes stored breast milk is described as tasting very sour or rancid after storage in the fridge but particularly after freezing and thawing.
Breast milk can be stored in the freezer (at 0° F or colder) for up to 12 months, although using it within 6 months is best.
Frozen breast/human milk safely lasts in the freezer for 1 month while preserving most of the nutrients; after 3 months in the freezer, there is a noteworthy decline in concentrations of fats, calories and other macronutrients.
Stomach cramps: Babies using spoiled, expired, or lumpy breast milk can cause stomach cramps, bloating, bloating, upset stomach, and fussiness. Food poisoning: Often spoiled breast milk will be contaminated, causing the infant to be infected with bacteria and have diarrhea and vomiting.
The fat component can appear as white spots in your frozen milk. You may notice that the fat separation occurs at the top of the container. For example, if you store your breast milk in bags that were initially frozen laying flat the white spots will be at the front face of the bag.
Although the lipase process is normal, at high levels it can cause a metallic or soapy aftertaste, exactly like what I had detected, and make the milk unappealing. The change of taste can happen within a few hours to days.
The results suggested an increase in umami and saltiness in milk from inflamed breasts, which might have resulted from an increased content in factors associated with umami and sodium. These specific taste changes might be associated with infants refusing to suckle from breasts with mastitis.
Results: Significant declines in bacterial colony counts were seen from 2 to 12 weeks freezer storage for all bacteria. There were no differences in colony counts between freezer types. Once thawed, no further bacterial growth occurred. Conclusions: Short-term freezer storage for 12 weeks resulted bacterial killing.
Lightly heating the milk in this manner deactivates the lipase in the milk, which can help eliminate the soapy tastes frozen breastmilk sometimes has. Scalding should ONLY be done if baby refuses to drink your frozen milk. This is because scalding destroys a small amount of the milk's beneficial properties.
Some of the anti-infective properties are lost when milk is frozen—but it still helps protect babies from disease and allergies and is far superior to any formula.
However, extra lipase can speed up this process, which can make the milk taste sour or soapy after some time has passed. (You might also find that your breast milk smells like vomit, or eggs, or metallic.)
Freezing Habits and Lipase
Freezing and thawing breast milk can have a big impact on taste and smell. Some moms notice that after defrosting, their milk smells unpleasant – soapy or even sour. This is normal! Breast milk contains lipase, an enzyme that is normally present in human milk and has a lot of benefits.
The milk may separate slightly, the flavor and odor may change slightly, and the texture may be grainier.
If you have frozen milk in your freezer that your child refuses. Some options: Try mixing the “rejected” frozen milk with fresh milk. Start with half frozen, half fresh and adjust the amount of frozen milk up or down depending on your child's preferences.
Increasing temperatures from 0 ºC to around 45 ºC will reduce the time taken for the lipase to break down the fat in milk. Over this temperature, the time taken will increase, or perhaps the lipase will not work at all.
Overheating also damages breast milk, destroying many of the essential nutrients your baby needs (2). If you accidentally overheat a bottle of breast milk, you can cool it down, and it will be safe for your baby to drink.