Is it a sin if one unintentionally had pork (or anything haram)?

I went to a restaurant with my family today. And it's not a halal shop so ordered seafood and vegetarian dishes letting them we cannot have pork and they know about halal. We ordered one dish with xo sauce and when I came home, found out from my sister that xo sauce normally always contains pork. So, does having pork (or anything haram) unintentionally considered as a sin? If so, why and what should one do about it?