Here "heart" is a metonym for a person's inner being or mind. Here Jesus means that food does not affect a person's character. Alternate translation: "it cannot go into his inner being" or "it cannot go into his mind" (See: [[rc://en/ta/man/translate/figs-metonymy]])
Jesus uses this question to teach his disciples something they should already know. It can be expressed as a statement. Alternate translation: "Whatever enters ... latrine." (See: [[rc://en/ta/man/translate/figs-rquestion]])
It may be helpful to explain clearly what this phrase means. Alternate translation: "all foods clean, meaning that people can eat any food without God considering the eater defiled" (See: [[rc://en/ta/man/translate/figs-explicit]])