Ever sighed at having to toss out a bottle of water at airport security? Then consider Jessica Coakley Martinez, who was forced to throw away almost four gallons of breast milk at London’s Heathrow Airport, the Washington Post reports.

“This wasn’t some rare bottle of wine or luxury perfume I was trying to negotiate as a carry on,” Martinez writes in a 1,588-word Facebook post to Heathrow security. “This was deeply personal. This was my son’s health and nourishment.” In her post, Martinez says she balances motherhood with a job that involves travel by pumping whenever she can—in public bathrooms, conference rooms, closets, you name it. Here the Californian had amassed a big block of frozen breast milk while traveling without her infant on an eight-city, 15-day business trip through Europe, where four countries had already allowed the milk to pass, the Sunreports.

Seems airport security at Heathrow’s Terminal 5 went by the letter of Department for Transport rules, which set the liquid-size limit at roughly 3.4 ounces unless the passenger is boarding with a baby, the BBC reports. Martinez’s argument: More than 300 ounces of her 500-ounce milk supply was frozen, not liquid, and she was willing to put it in checked luggage. Security apparently said the milk might “melt and become a liquid,” and she couldn’t check it because she had already crossed a border — so they confiscated it. Martinez says she begged, pleaded, and even cried “out of sheer shock and desperation,” to no avail.

“Beyond literally taking food from my child’s mouth, you humiliated me and made me feel completely defeated as a professional and a mother.” Heathrow says it was only following British law.