I doubt customs would let it through. They are very fussy about plant material. Even if it is vacuum packed etc. They are essentially a raw product. The concern is unknowingly bringing a foreign disease in. Just ask the folks in Florida about this. In the past decade, two foreign diseases have been decimating the citrus trees there. Many orchards have been destroyed. Diseases that came in on a tree some smuggled in.
It can be done if the supplier goes through the hoops for their hops. Lots of Dutch bulbs make it to this country, but the suppliers get phytosanitary certification from the USDA which gives them the ability to import.