Hiya, there's a sticky thread at the top of the first tri board which will help you.
Mayonnaise from jars etc is fine, you just need to be careful with home-made stuff in small cafes etc as that usually contains raw eggs which can then lead to salmonella.
I've also been told to make sure meat is cooked all the way through - no more rare or medium steaks

and the same with fish. Most fish is ok when properly cooked but no raw fish and there are a few you have to be careful with because of mercury levels. But read that thread, its really helpful xx