I made a horrific discovery this morning. Some of my pump connectors and valves had mold in them! The set on the bottle drying rack that was left horizontally instead of vertically must have had water trapped in them, causing the mold to grow. The worst part is, I threw away 2 bottles of milk I pumped yesterday just in case it came into contact with the mold!

1) completely assembled pump kit; 2) breast shield; 3) connector; 4) valve + membrane; 5) tubing; 6) Medela In Style Advanced (If you have a Medela Freestyle, the connector is going to look a little different)


When I was pumping for Charlie, I was very meticulous about washing my pump parts. I washed each piece individually in hot, soapy water after each use, and regularly sterilized them too.

As with most everything when it comes to second children, I’m much more lax. Olive’s nanny washes my pump parts now, but I’ll wash them once in awhile, and I admit that I’ve been lazy about disconnecting the valves and membranes. Well I’ve certainly learned my lesson and am not only going to wash my pump parts much more thoroughly, but I’m also going to sterilize them regularly as well.

I mentioned in a previous post on my pumping strategy that I keep my pump kit assembled in the refrigerator and use the same kit throughout the day (from 9am – 6pm), and then wash it at the end of the day. This way I only need one pump kit and don’t have to do dishes throughout the day. It took me a very long time to figure that out — I never did it with Charlie — and I thought I was so smart. But when I googled it today, apparently tons of moms had already been doing the same thing! It’s particularly practical for working pumping mamas.

Here are some more tips for storing and keeping pump parts clean:

– If you decide to go the refrigerator route, flush the pump kit with hot water after each use without disassembling it, and then store it in tupperware in the fridge. Many moms omit the rinsing, and I have too depending on how time crunched I am. I’ll even store the entire pump kit with bottles attached in the fridge.
– To hide your pump kit in a shared work refrigerator, stick it inside a ziploc bag or tupperware container, then put it inside a paper bag or lunchbox.
– If you opt to clean your pump kit after each use at work, you can use Medela Quick Clean Wipes or Medela Micro-Steam Bags for fast cleaning.
– To wash your pump kit, separate all your pump parts, including the connectors, valves, and membranes, and wash them in hot soapy water or in the top rack of your dishwasher. I typically hand wash everything, but when I was using the dishwasher, I’d still wash the valves and membranes by hand since the membranes were so fragile. A nipple brush works great for getting into the tiny crevices.
– Have backup membranes because membranes deteriorate with use, and the pump won’t work if a membrane has a tear in it.
– To sterilize pump parts, boil them for 10 minutes, use a Medela Micro-Steam Bag or electric sterilizer. There is no recommended guideline for sterilizing, except maybe if you have a preemie, and some moms never sterilize.
– Regularly inspect your pump tubing because condensation can cause mold to grow in the tubing (this is very common and has happened to me).
– Water can get in the tubing if you use pump parts that are not completely dry.
– Run your pump for a couple minutes after you detach your pump kit to remove any condensation left in the pump tubing.
– Clean your tubing any time milk goes inside them (though this has never happened to me in my hundreds of hours of pumping).
– To sterilize the pump tubing, detach the plastic ends, wash everything with warm water and boil for 10 minutes. Place the plastic ends back on when the tubing is warm. Then hang vertically to air dry, or attach to your pump and run until water evaporates. You can also add a little bit of isopropyl alcohol after you finish boiling.

What is your pump cleaning regimen?