Food Safey Question

Just realized I left the salt shaker thing sitting out on the counter all day yesterday and me and my roommates all used it last night with our microwaved fries & Chicken nuggets.

Are we all about to get really sick? Should I tell them or just blame it on the food? What do I do with what's left? Trash it? Wash it in something?

btw, if anyone could tell me what the difference is between pork, beef, and chicken it would really help.