Praise be to Allah, and peace and blessings be upon the Messenger of Allah and his family.
Pork is impure according to scholarly consensus, because Allah, may He be exalted, says (interpretation of the meaning):
{Say, "I do not find within that which was revealed to me [anything] forbidden to one who would eat it unless it be a dead animal or blood spilled out or the flesh of swine – for indeed, it is impure – or it be [that slaughtered in] disobedience, dedicated to other than Allah} [al-An‘am 6:145].
If the worker touches the pork, then put his hand in the wet vegetables, that makes them impure. Similarly, if he cuts a pizza on which there is pork with a knife, then uses the knife before washing it to cut another pizza, that makes it impure, and it is well known that it is not permissible to eat food that is contaminated with impurity.
The basis for that is the report narrated by al-Bukhari (5478) and Muslim (1930) from Abu Tha‘labah al-Khushani, who said: I said: O Prophet of Allah, we are in the land of some of the People of the book; can we eat from their vessels? He said: “If you can find other vessels, then do not eat from them, but if you cannot find other vessels, then wash them and eat from them.”
This is to be understood as referring to someone who uses their vessels in which there are impurities, as in the version of this hadith narrated by Abu Dawud (3839): We live close to some the people of the Book and they cook pork in their pots and drink wine in their vessels. The Messenger of Allah (blessings and peace of Allah be upon him) said: “If you can find something else, eat and drink from it. If you cannot find anything else, then wash them with water and eat and drink.”
The scholars of the Permanent Committee for Ifta’ were asked: Some restaurants grill beef on the same hotplate as pork. Is it permissible to eat that meat? Similarly, they use the same knife to cut the meat.
They replied: It is not permissible to eat beef that is grilled on the same hotplate as pork. The same applies to the knife."(Fatawa al-Lajnah ad-Da’imah 22/285).
Please see the answers to question no. 465771 .
If you are certain that the worker washes his hands before touching the vegetables and dough, and he washes the knife before cutting the pizza, it is permissible to eat those foods that are permissible.
If you are uncertain about that, it is not permissible, because the basic principle is that the impurity remains on his hand and on the knife after touching the pork, and this uncertainty cannot be dispelled unless you are certain that he has washed both.
And Allah knows best.
