After having crossed the borders a few times (both ways) we've come to the decision to run down our home refrigerator in advance of the trip, then we've taken what's left with us in the RV, if we lose it at the border then it's not a big thing as the rules seem to change frequently. We declare what we have and then have the banned stuff dumped. We have enough frozen food meals to keep us fed for a few days then we do a major shopping at our convenience.
Be prepared for a bit of "sticker shock" when buying food and booze (and for eating out)in Canada compared to the US!