Breastfeeding is great…but being connected to a wee creature by the boob is not so great. I knew that if I wanted any freedom at all in the first year, I was going to have to pump and store my milk. And so I did. And the little bottles and bags of boob milk populated our freezer…and all was well.
Until, I defrosted some milk that was 6 weeks old and tried to feed it to my son. He gave me a look and screamed and refused to take it. I don’t blame him…that milk smelled funky. I would have refused to drink it too. I thought that maybe my storage system was flawed. I checked the temperature of the freezer with a snow thermometer (-20 deg C)…I expermented with freezing in different types of containers…and in different areas of the freezer. I thought maybe it was freezer burn so I started putting containers into ziplocs…I mean, all the resources I had said frozen breastmilk was good for 4-6 months.
For those that are new to this (as I was), all human milk contains some enzymes. Lipase chews apart fats. If your breatmilk contains a lot of lipase, it will start to digest itself and over time that leads to a “soapy” smell. The milk is still safe for consumption, but some babies don’t like the way it tastes or smells. Lipase is obviously not a problem if you and your babe are going to be joined at the nip, breastfeeding on demand. But if you are looking to store milk for any reason, it can wreck havoc on your frozen stash. I read stories about women having to toss or donate hundreds of ounces! Hundreds! I felt bad enough about tossing 20 ounces.
Enzymatic reactions are temperature sensitive…lipase will chew apart human milk more quickly at room temperature than it will milk that is in the fridge or the freezer…but eventually chew it apart it will. Lipase can be deactivated through heat…in the chem lab they call this “denaturing” a protein. If you heat it up enough, it will unfold and loose its function but it won’t refold properly to regain function on cooling…much like cooking an egg white denatures albumin.
I could have just started scalding all of my milk, but scalding milk is time consuming and will destroy some of the good stuff in breastmilk along with the lipase…stuff like antibodies and vitamin C. Plus, I’m a science nerd so I felt the need to do an experiment.
I pumped 4 ounces of milk and split it into two containers. One I left alone (my control) and the other I tried to “scald.”
Scalding means to heat to just below boiling and I read that for breastmilk, 180 degrees F was the desired temperature. I was afraid of scorching or burning the milk so I decided to use a double-boiler set up…and I used my meat thermometer which was the only kitchen thermometer I had. And then I proceded to stand there and stir and watch….for an hour.
The milk only got to 150 degrees. At that point, I said, screw it, and dumped it into a sauce pan and put it back on the heat. I couldn’t use a thermometer anymore because the level of liquid was too shallow but it bubbled around the edges without coming to a full boil. So I dumped it in a bottle and set it in an ice bath to cool rapidly.
Here are the two samples (sorry about the crappy photo):
Notice how the “scalded” sample has about half the volume? Turns out my slow double-boiler process made a breastmilk reduction. Mmmm mmmm yummy.
I put the two samples in the fridge on day zero and smelled them every day. By day 3 the non-scalded sample was starting to smell a little off…but today (day 4) it was clearly skunky.
So there I had it…I had some kind of an excess enzyme problem (probably lipase) leading to accelerated breakdown of my boob milk. Now I’m going to scald everything before I store it…and I’m really ramping up my stash as I prepare to go back to work.
Through my internet “research”, I found anecdotal evidence that breast milk could be heated to 180 degrees F to destroy the lipase or to 145 deg F for 1 minute. Now I put my milk in a sauce pan and once it hits 145 degrees keep heating it for a minute..the process takes about 3 minutes total. I have read some interesting things about scalding using a bottle warmer but since I don’t have a bottle warmer, I’m probably going to stick with my saucepan method for now.
I also read some anecdotal evidence (okay one posting on the LLL forum) that increasing your dietary intake of omega-3’s will decrease lipase production in boob milk…ah omegas…is there any health “problem” you haven’t been touted to fix? Now, I don’t believe this for a minute…I need way more than one anecdote to buy into something but it did remind me that I have a bag of flax meal languishing in the fridge. At one point I thought flax meal was good for me but for one reason or another (all of them probably related to 18 lbs of tiny human), I stopped eating it. Now I’m adding it to all kinds of stuff. I don’t expect this to help my lipase problem at all but it was a nice reminder to eat my flax.