Why are food workers required to know the importance of proper dishwashing?

To prevent a health risk from poor sanitation. 

In my opinion I think that food workers are required to know the importance of proper dish washing because if a restaurant doesn't wash dishes properly it can cause a minor food disease pandemic which would lead to the restaurant being shut down lots of people with food diseases and can possibly cause deaths depending on how awful they did.   Hope this Helps ^.^ 

Your best answer would have to be a.deciding whether to build a new baseball diamond at a nearby park.