Alyssa Milano is not happy. And it's no wonder. Milano just experienced something that many breastfeeding moms on the go have also been through: the dreaded airport security breast milk confiscation.

Ask any breastfeeding mom how hard it is to pump and store breast milk, especially while traveling, and she will explain why pumped breast milk is considered liquid gold for breastfeeding mothers.

So you can imagine how unhappy Milano was when about 10 ounces of her breast milk was confiscated by airport security today at Heathrow International Airport.

The actress — mom to 3-year-old son, Milo Thomas, and 7-month-old daughter, Elizabella Dylan — turned to Twitter with her frustration. "Gone," Milano tweeted. "Not okay."

For their part, officials at Heathrow tried to respond to Milano's tweets:

But Milano did not let up:

And for the grand finale:

Milano's unfortunate incident serves as a good reminder to nursing moms to check and recheck airport security procedures regarding traveling with breast milk. In the U.S., breast milk is considered a medically necessary liquid. According to the Transportation Security Administration, moms who wish to bring more than 3.4 ounces of it on the plane in their carryon bag must simply notify the TSA agent before the screening process begins. But with airport policies that change more frequently than a new parent changes a diaper, it's good to know what you might be dealing with when you travel — especially if you plan to travel without your baby.

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