There is a cooling truck from 1962, but I notice now that the dat-file says it only takes fish. But the cooled wagon definitions say they only take food, yet they can carry fish in practice, so I'm not sure how the dat definitions work.
Do milk ships really exist? But I see the problem if a ranch or dairy is generated on an island. I guess the real world solution would be a general purpose ship, or a ferry carrying a milk truck. A reefer ship would be nice, though.