I freeze in the hotel fridge/ pass to them to make sure it goes into freezer. On the day I come back, I took from hotel before I go to airport, I gave styrofoam box to store the frozen milk, will put cooler pack, and ice inside. Then I seal it tight. Work ok for me in both trip - Hong Kong & Bangkok. About max 4-6 hours out from fridge till I land and quickly go home and freeze again.
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