It's all going to depend on whether you get the red light or not. Yes, they can still pull you over if you get the green, but I don't believe that happens very often. If you get the red light they will most likely check your cooler. If you're bringing things on the "no" list, I suggest you bury them underneath ice, or in your luggage. Even if that means having to pull over somewhere else and put them back in the cooler. I don't bring food with me, I like buying my food down there. But I do understand that there are people with food allergies who don't have the option. If that's not your case, then save yourself the worry and just buy food down there. It tastes better and you're helping the local economy.