The only thing we've ever been asked about at the crossing into Alaska is oranges. Hubby was asked about his Moose Drool t-shirt once - the American agent wanted to know where he got it because he liked that beer. At one crossing as we were heading to Haines, I admitted to having oranges that I'd forgotten about that morning (or we would have ate them). The agent asked me if we planned to eat them in Alaska. I told him no. He let me keep them as long as I promised to bring the peels back to Canada if we did happen to eat them in Haines.
They aren't as fussy about produce or meat in the north, because farming isn't a big thing up here so there is less threat to those industries. I think they also appreciate that it is more difficult to get food - many people in Beaver Creek shop in Tok and take their groceries back to Canada. We usually don't even think about the food we have, but do prepare a list of alcohol because we're often asked about that.
