When the food is implied to be so obscenely bad that it is censored for the sake of your sanity or ability to avoid puking. It is a common comedic device.
Sometimes, the food is being censored for a sexual reason, such as it looks like human genitalia or its going to be used for a sexual reason. Such cases, specially the former, should be tagged as sexually_suggestive instead.
This tag implicates censored (learn more).