You are allowed to give whatever comes into your possession freely to non-Muslims as they are allowed to consume these things. Such foodstuffs are considered wealth which can be acquired and used by them, and as such you are allowed to give them away for consumption, but not as charity. Regarding a supplementary question of what constitutes Haram food, people must remember that we are living in a non-Muslim land where there are a multitude of things that we cannot eat because they contain animal fat or alcohol etc. Muslims, both purchasers and providers, must be very careful, but not over-zealous when choosing foodstuffs. The best solution in cases where you are unsure of any particular ingredient is to immediately write to the manufacturers.
Manufacturers tend to be very co-operative and helpful.