Reusable item

Helo, sorry for the gramatical mistake that i can make, I'm french ^^'

I wanna do a mod for adding more food and i want to make a knife.

I don't know how to do for making the knife reusable and not be consume by the craft

for exemple i want to make slice of bread by using a bread and a knife, and i want the knife donc be consume by the craft, if someone can help me to find a tutorial or say how can i do ^^

thank a lot ^^