Do you notice milk or condensation in your backflow protectors after pumping? Did you know that there’s actually nothing to worry about when this happens? Your backflow protector is working exactly as it should by preventing milk and moisture from entering the tubing. If you’re consistently finding milk in your backflow protectors after you pump, it simply means you have a strong letdown – and that’s a good thing!
What can I do if there’s milk in my backflow protector?
That’s easy. Just pop it apart and wash it like you normally would with your other pumping kit accessories. Remember to make sure your backflow protector has enough time to completely air dry prior to assembling it again. 🙂
Parts & Accessories
When should I replace my backflow protectors?
You do not need to replace your backflow protector every time milk gets in it. This just means your backflow protector is working as it should and you simply need to wash and dry it with the rest of your pumping kit. That being said, the silicone membrane in the backflow protector does wear down over time and use elasticity. You’ll need to replace your backflow protectors regularly to maintain good suction and performance of your pump (not replacing them means you can lose suction gradually over time, and the pump motor has to work harder to maintain suction which can wear down your pump more quickly than usual). If you’re pumping once or twice a day, replace these every 6 months; if you pump more often or are an exclusive expresser, replace these every 3 months.

Spectra M1 Portable Single Electric Breast Pump
Spectra Manual Pump Switch Kit
Spectra S1+ Hospital Grade Double Electric Breast Pump with inbuilt rechargeable battery
Spectra Handy Plus Manual Breast Pump
Spectra 9 Plus Portable Double Electric Breast Pump
Spectra 27mm Narrow Neck Breastshield Set [Dew 350 only]
Backflow Protector for Handsfree Cup [Pack 1]
Spectra Milk Storage Bags [Box of 30]
Spectra Wide Neck Milk Storage Bottles [Pack of 2]
Spectra Milk Cooler Kit
Spectra Duck Valve [Pack of 2]
Premium Spectra Backflow Protector [Pack of 1]
Spectra Wide Neck Slow Flow Teats [Pack of 2]
Neck Adaptor - Wide Neck Shield to Narrow Neck Bottle [Pack of 1]
Spectra Replacement Tubing [Pack of 1]
Spectra Valve Head & Membranes [Pack of 2 of each]
Diaphragm For Backflow Protector [Pack 2]
Spectra Blue Valvehead [Pack of 1]
Spectra Backflow Filter - Dew350 [Pack of 3]
Spectra Dew 350 Tubing Connectors
M1 Adaptor for Double Pumping
Nozzle cover
M1 Short Tubing [Pack of 2]
Spectra S2+ Hospital Grade Double Electric Breast Pump
Spectra Power Cord + Adaptor 9V
Spectra Valve for Handsfree Cups [Pack 2] 
is it ok to just replace the silicon membrane? Not the hard plastic part?
My husband mixed up some older backflow protectors with some newer ones I just got and now I can’t tell which are which. How can I tell which ones are the old ones?
Oh no Stacey! Unfortunately there is not a simple way to determine this. 🙁
I am so sorry. 🙁
There is a small amount of condensation in the little connector piece that connects the backflow protector to the breast shield at the end of each pumping session. Does that mean the backflow protector parts need to be cleaned every 24 hours, or is it okay to just let it dry? I haven’t seen condensation or milk in any other part of the backflow protector.
Hi Katy, we would recommend making sure your backflow protectors are dry to start pumping to avoid that moisture travelling to the tubing.
You should wash your backflow protectors in hot soapy water with your other parts, at least daily – even if they seem dry – to avoid any build up of mould or bacteria.
Washing parts thoroughly is important for your little one’s health. 🙂
Let us know if we can help with anything else. 🙂
I just found mildew in my Backflow protector is my milk safe to use? I haven’t been washing these parts daily and have no idea how long mildew has been present!
Hi Maggie, unfortunately we cannot answer that for you. 🙁
I personally would not be ok with it, but some mums would be. There are different ideas about this, so you will need to draw from your own opinion about how appropriate this is for your little one.
I would replace all my shield kits though, as mould spores can travel and cannot be seen and cannot simply be sterilised to remove. 🙁
I discovered a very small amount of green liquid in the backflow preventors.Im not sure what it was,possibly bad milk.
Does that mean the milk is contaminated eventhough its a closed system pump and we have to throw the milk away?
Thank you
Hi Milo, oh wow! I am not sure what that was. It could have been mould, or just milk from something you ate.
I would give everything a good clean, and I can’t advise about what you should do with the milk, as I don’t know what happened I am afraid. 🙁
If in doubt I would discard of it. 🙂
Good luck.
I wish I had found this post sooner. I found mold on my back flow protectors. Do I need to throw away the milk?
Hi Mel, oh gosh! I am sure that is a surprise for you. 🙁
That is a personal decision.
If a mum is using a pump that is not a closed system, there is a high chance there is mould in their motor and mould spores could travel to their baby’s milk. Some mums would say this is fine, others would not be ok with it.
I cannot suggest what the best thing to do in this situation would be… for myself, I would dispose of it, but that is just me. 🙂
Glad you discovered it so now you can replace your complete shield kit to avoid any further issues.
Do I need to wash the back flow protector every time milks gets in? Is it safe to give baby milk pumped when there’s some milk from a few days (possibly) in there? Thanks!
Hi there, and thanks for a very good question. 🙂
You do need to wash it every twenty four hours if you are getting any condensation in there, to avoid mould forming.
It also prevents moisture getting into your pump, which could lead to damage and mould, so you really want to do what you can to keep those backflow protectors dry after your pumping session, making sure they are cleaned every twenty four hours, and air dried completely prior to assembling again.
Whilst the condensation from your backflow protectors does not come into contact with your baby’s milk, it is bacterial and mould spores, which travel and are not visible, you want to be sure to avoid in the milk, and the motor.
If you have any further questions, please let us know, and we will get them answered for you as best we can.