🍼 Breast milk

Nothing adverse — breast milk is explicitly exempt from the 100ml liquid rule in the US, and you can carry it in any reasonable quantity. TSA officers will ask you to remove it from your bag for separate screening, which may include opening containers for testing, but it will not be confiscated simply because the volume exceeds 100ml.

No — TSA's rules do not require a baby to be present. You can travel alone and carry breast milk without any obligation to prove you have an infant with you. The same applies in the UK, EU, Canada, and Australia. Simply declare the breast milk to the officer at the checkpoint and present it separately for screening.

TSA may test breast milk using a liquid scanner or X-ray without opening the container, but they are also permitted to open the container for testing if necessary. You can request that officers do not open containers, and they will make reasonable efforts to use non-invasive testing first. If you object to any testing method, the item may not be allowed through. Arriving at the checkpoint with a few extra minutes to spare makes the screening interaction easier.

Freshly expressed breast milk can be kept at room temperature for up to four hours and refrigerated for several days, but for longer journeys you will want an insulated cooler bag. Ice packs and gel packs used to keep breast milk cold are also exempt from the liquid rule when they are frozen solid at the checkpoint — if they are partially melted and slushy, they become subject to standard liquid rules. Freeze your ice packs fully the night before travel.