I have been using some Lansinoh storage bags I had leftover from my first baby in 2011 with my second baby currently. In defrosting some of the milk i froze about 3 months ago, I am noticing a fish-like smell on the outside of the bags (no fish in the freezer at all, have separate subzero freezer for milk) that has seeped into the milk itself. The milk has a fishy aftertaste, the older the milk, the fishier. I have never had this problem with my first baby and I pumped/stored for 18 months then. Is this the lipase issue, or could it be the plastic bags have degraded over time? I defrosted a bag from about a month ago and it tasted and smelled like fresh milk, no fishy smell or taste. I know what rancid milk smells like and it doesn't smell "rancid," it smells fishy. I threw away about 2 gallons this weekend because it smelled/tasted so bad. My pumping procedures are strictly clean (I am a nurse) and I always refridgerate my milk immediately after pumping. None of my refridgerated breastmilk has this issue, only the frozen milk in the Lansinoh bags. Please help. I don't want to throw away any more precious milk!
Stella, Thank you for your question. There would be nothing in the production or process of making the bags that would cause them to degrade over time or have a smell or taste such as what you are experiencing. Are you taking any fish oil supplements by any chance? That can, in some cases, make your milk smell and taste fishy. If not, it could very well be lipase that is causing this issue. Unfortunately, there is nothing that can be done once the milk has been frozen but there are things you can do to the milk prior to freezing such as scalding it to ensure that you deactivate the lipase. Here is a link with more information: https://www.lansinoh.com/articles-videos/storing-breastmilk. In either case, babies will sometimes take the milk and it is not necessary to discard it unless, as you experienced, it was too overwhelming a smell or taste.