Hygienically is how you do something when you do it in a clean way that stops germs from spreading. You wash the board hygienically, store the food hygienically, throw waste away hygienically. It does not describe a thing; it describes the manner. Same idea as hygienic, only this form goes with a verb. In careful or official English — hospital rules, food safety — you will see it; in casual talk people say “keep it clean.” Though actually, saying something was done hygienically is a claim about germs, not about looking neat. A shiny counter can still fail the test.

衛生地