Depends on the context. If it is written/talked about in a geographic context, it will usually mean “the Americas”. If it’s in a political context, it will mean “the USA”.
Keep on mind that reputable news outlets won’t use “Amerika” when referring to the US however, they will use “Vereinigte Staaten” (United States). “Amerika” as a term for the US is very much a colloquial thing.
3,5% milk is also the standard milk here in central europe and it says so on the packaging. People call it simply “milk”, but it clearly says 3,5% milk on the branding.