Is it permissible to eat pizza that does not contain pork if it was cut with the same knife used to cut pizza that does contain pork?

A knife used to cut pork or something impure is considered impure. If it is then used to cut lawful meat or pizza, whatever it touches becomes impure, and it is not permissible for a Muslim to consume it. However, the cook can purify and clean the knife after using it for pork. If this is done, then there is no harm in using it for other things, and consuming what was cut with it after purification.