It does not matter what the Jews believed, what matters is what Jesus was saying.
Believed about what was considered 'food'? And you know you are including Jesus in that statement as he was most defiantly a Jew. And Yes, it does matter because what was food for God's people was determined by the Creator who made man as well as the other creatures.
Jesus was talking and so were the Pharisees
about germs, dirt that could be on your hands. Today we all know about that if not before. It is the unseen thing that can hurt. Yes, the food, goes into the stomach and goes through the digestion process. However if you touch your food with unclean (unwashed) hands you may have added more to it than you can see.
There is a difference between it making someone sick and what Jesus was talking about. They were considering it to eat with unwashed hands a way to 'defile' a person. You need to understand what that means and it has nothing to do with him 'declaring all food clean'.
He didn't have to declare all food clean as it was already done through Moses of what was clean and what wasn't.
Defiling oneself he was speaking of was not by eating with unwashed, dirty hands but by the things that proceed out of the mouth that either raises him to be righteous or unrighteous.
Your reasoning here is imaginative, I will grant you that, but I don't think it works. The challenge you face is daunting: Jesus says that nothing that goes into a man defiles him. It appears that you are trying to argue that when Jesus says this:
there is nothing outside the person which can defile him if it goes into him
He was speaking of he dirty hands, not the food (defined by God as Fit to Eat). If it was already declared 'clean' thus being called ' food' then how does it suddenly switch to taking unclean things and making them fit to eat. Just how would that happen?
.....Jesus is effectively saying this instead:
there is no food outside the person which can defile him if it goes into him
That's because he was talking about what got on the food from the dirty hands.
And since Jews, including Jesus, did not consider pork, etc. to be food, the scope of the "nothing" excludes food.
There are things which are alive that are considered by their CREATOR to be Fit to eat for his people. Anything not included in the Torah about that list is NOT considered Food. Just as you wouldn't include a car as food or a cell phone as food or a bedsheet.
The Creator has the priority and absolute authority to make those distinctions, not mankind, Jew or Gentile.
There are a big problem with this: As you guys often do, you gloss over the explanation that follows Jesus' initial statement:
Do you not understand that whatever goes into the person from outside cannot defile him, 19 because it does not go into his heart, but into his stomach, and is eliminated?”
Not glossing over anything, and am not a guy so please don't refer to me as such.
Yes, he was speaking of being made unclean, by eating clean food with unwashed hands.
The point should be obvious: even if we grant that Jews did not consider shellfish, pork, etc. to be "food", these things will, if taken in, "go into the stomach and be eliminated".
No, God the maker of all things considered them to not be something to be 'taken into the body'.
Is a piece of shellfish something that would "go in and be eliminated"? Obviously yes. And Jesus's audience, even if they themselves, did not consider shellfish to be "food", they would know that others do.
Others do what? This conversation was not about the heathen gentiles, but the Jews and the Laws of God as well as the man-made laws he was contending with them about.
If Jesus was really thinking along the lines you are, he would not have offered this kind of explanation as a follow up to His initial statement.
No, I think along the lines he did as I know where and have studied where his teaching came from.