Ketchup is NOT a Polish food, end of. It's a food eaten in Poland but that doesn't make it Polish
Even stuffed cabbage rolls aren't Polish. What is one uniquely Polish food?
Now you are talking funny . Do you think that a certain product becomes strictly American because once upon a time , one american made a tomato sauce , put it into a bottle and labelled it as ketchup .
I will not respond to your absurd comments.
You talk nonsense ( not the first time I remember matura thread and your suggestion that a colloquial name is used in formal translation , a lot of people gave a link to the official polish ministry of education where the name of Maturity Certificate was an official name , but you were still clutching to your false opinion ) .If you can`t even admit that sometimes you are maybe wrong , it seems to me that your comments are not valuable.
My answer is contained in the question -
How do you know that there was no tomato sauce ( brand name - ketchup )in the stone age? Maybe few tribes invented it in the same time - Slavs or Celts, maybe Chinese or Native Americans had the privilege to taste it before americans . What made you so sure about that LOL.