Security staff told her she couldn't bring it on the plane unless she had her baby with her, Ms. Brewer-Davis said. But according to Transport Canada regulations, she should have been able to keep at least some of the milk.
The 31-year-old California mother said she was away from her child for 51 hours while at an academic conference, during which time she pumped breast milk every three hours. Having to throw out the milk she planned to bring home to her baby felt "violating," she said.
"I don't think I'd realized quite how important it was to me until that moment," she said.
"It represents the mother's connection to her baby and this rule fails to recognize the importance of what pumped milk represents. ... Forcing me to throw out the milk represents more than an inconvenience: It devalues this connection between me and my baby."
She said the breast milk filled 10 bags ranging from 60 millilitres to 180 millilitres. She had about 1½ litres in total, and was carrying it in a cooler.
"I was very upset. ... It represented a lot of work and a lot of time and it was something that was very important for me to bring back to my baby."
She said it's absurd to prohibit nursing mothers without their children from bringing breast milk on a plane, because if they had their baby with them they wouldn't need to carry breast milk around. Being without the milk meant she didn't have the supply she hoped to have when she got home.
"I expected to come home and have lots of milk for the rest of the week because I still have to work when I get home," she said. "I mean, she's not going hungry or anything, but we don't have any wiggle room."
Canadian Air Transport Security Authority spokesman Mathieu Larocque said breast milk is subject to the same regulations as any other liquids, gels or aerosols. The restrictions have been in place since August, 2006, in the wake of the failed bombing attempts at Heathrow Airport in London, where 24 people were arrested in a plot to detonate liquid explosives on passenger aircraft.
In Canada, passengers can bring containers of 100 millilitres or less as long as all the containers fit in a one-litre, resealable plastic bag. Baby food, formula, milk, water and juice are exempt from the restrictions if the passenger is travelling with a baby two years old or younger.
Mr. Larocque said he doesn't have any details about the incident, but a passenger in that situation should have been able to keep all the containers that were 100 millilitres or under and fit inside a one-litre bag that security staff would have given her.
"She would have been allowed to keep her one-litre resealable bag and the containers of 100 millilitres or less in that one-litre bag," he said.
Ms. Brewer-Davis said security staff didn't mention size restrictions or tell her she could keep some of the milk. "They said it would have to be thrown out without looking at the containers or the quantity," she said, adding that she called CATSA afterward to complain.