It looks like Spudqueen has answered for me. (Ta, Spudqueen). I've known friends take various types of British food into the USA and I've never heard of any significant problems.
Your only difficulty might actually be in finding some discounted puds in the supermarkets. I usually buy some myself around this time of year but I've not seen any in my local supermarkets. (The nearest Morrison's, for example, sold out of all their Christmas puds several days before Christmas).
Chris