Fact of the Day: Milk Fat: Pump that heavy cream

Human milk changes in its composition throughout lactation as your baby grows and is constantly changing to meet the needs of the baby from the first few days of colostrum to beyond the baby’s second year. The composition of your milk can change  from day today especially as hormones ab and flow with your menstrual cycles. They can change during a given day  based on your stress levels, how often your baby feeds, and how well your baby MDs your breast. But did you know that the composition of your milk can also change during an individual feeding  and from breast to breast?!?!  As the baby eats, protein and fat content rise in the milk. There is actually 4 to 5 times more fat and 1 1/2 times more protein present at the end of the feeding than at the beginning. The baby may consume nearly 18% of their calories between minutes 11 and 16 of a feeding.  The fat content at the beginning of a feeding is around 1% milk fat. By the end of a 15 to 20 minute feeding, the fat content can be as high as 4 to 5%! By comparison, whole milk contains just 3.25 percent milk fat.  Fat content varies from mother to mother and from feeding to feeding. The amount of fat in breastmilk is dependent on the length of time between feedings, the degree of breast fullness, and the length of time the baby sucks at the breast. To put it simply, the emptier the breast, the higher the fat content. The fuller the breast, the lower the fat content. By trying to “stretch” a baby to scheduled feedings actually decreases the fat content in a mothers milk. It is always best to feed baby on demand.

Pumping Log : Storage

We’ve talked a bit about increasing milk supply and about pumping. So now that we have all this yummy milk, what are we going to do with it? Let’s talk about milk storage.

The U.S. Centers for Disease Control and Prevention (CDC) offers ranges of time that milk can safely be left at for certain temperatures. Use this link to go directly to their website. But there is a simple rule that fits within these ranges and is easy to recall, even when you’ve had less sleep than a college kid in finals week. Just remember 5-5-5.

  • 5 hours at room temperature. If the room is very warm (more than 85 degrees F), 3-4 hours is a safer time range.
  • 5 days in the fridge (the back of the refrigerator is the best place to store your milk since it is the coldest.)
  • 5 months in a regular freezer (the separated compartment in a typical fridge/freezer unit) According to the CDC, milk frozen for longer than the recommended time ranges is safe, but may be lower in quality as some of the fats in the milk break down.

Other time ranges that don’t fit as neatly within the 5-5-5 rule, but are still helpful:

  • Human milk can be stored for 6-12 months in a chest or upright deep freezer.
  • Human milk can be safely stored with ice packs in insulated storage bags for up to 24 hours.

As part of my routine, if I work the next day, I put my milk into separate bottles and stick them in the fridge when I get home from work. That way my husband can feed them to my baby the next day while I’m at work. If the next day is a day off, I put my milk into disposable milk storage bags to stick in the freezer until the next time I work. The bags are labeled with the date they were pumped and always put in order from oldest to newest milk. This method saves going through a bunch of milk bags and saves both time and money. There are several brands of milk storage bags. I’ve found I really like the Dr Dudu bags. They’re larger size and with the double zipper I don’t need to worry about leaks in my lunch bag during the work day.

Milk from different pumping sessions/days may be combined in one container – use the date of the first milk expressed. I frequently pour all of my milk from one day of work into a larger bottle. This helps even out the calorie count and fat content since we know different pumping seasons yields different milk content. Avoid adding warm milk to a container of previously refrigerated or frozen milk – cool the new milk before combining. Breastmilk is not spoiled unless it smells really bad or tastes sour.

Safely Thawing Breast Milk

As time permits, thaw frozen breast milk by transferring it to the refrigerator for thawing or by swirling it in a bowl of warm water. You should avoid using a microwave oven to thaw or heat bottles of breast milk. Microwave ovens do not heat liquids evenly which could easily scald a baby or damage the milk. Bottles may explode if left in the microwave too long. Excess heat can also destroy the nutrients in your milk. It is recommended that you do not re-freeze breast milk once it has been thawed. Although I read on kellymom.com that if the milk had only been partially thawed and there are still ice crystals in it, you can safely refreeze the milk and thaw it on a later date.

When the fat in your milk separates in the fridge or freezer, make sure you swirl the milk to incorporate it back into a smooth, creamy mixture. Breast milk has living components in it which help protect your baby’s gut and promote digestion and immunity. Shaking breast milk actually denatured, or breaks down, the shaped molecules of the protective proteins, leaving them in pieces. Lactoferrin, lysozyme, and other protective components work their protection magic when they are in their original shaped molecular structure.

Other helpful website for breast milk storage Kellymom.com