What would you be charged with if you brought goods into the county illegally and were caught?

In the US, it's unlikely you would be "charged" with a crime.

Instead, foods are confiscated at borders and destroyed. This prevents certain insects and bacteria from crossing the border into the US food chain. This would include plants that are not indigenous to the US (including Hawaii and Alaska) because many can choke out native plants. They would confiscate live fish and animals for the same reasons. Birds are permitted, I believe, but only if declared an health certificate submitted.

Goods are a different thing. You would be made to pay customs, and likely a stiff fine for lying on the declarations form. There could be some goods they confiscate outright.

*The same things happen whether coming on foot, by vehicle, or airplane.