15:45 Jul 24, 2010 

There are many food items that retain their original name, sometimes with slight modification in pronunciation and/or spelling. Here are some examples of such food items:
hummus
tahina
tabboula
kabab
shawarma
kushari
Mousaka
nan
biryani
curry
masala
schnitzel
soufflé
meringue
mousse
petit four
hamburger
macaroni
spaghetti
fettucini
goulash
tres leches
caramel
creme brulée
fondue
...
...
...
etc.

Notice how many such items are spelled/pronounced differently when they are borrowed by other nations. In some cases, the meaning changes as well. Notice, for example, that in Egypt, the word "goulash" is used for something entirely defferent from its original meaning.

13:08 Jul 24, 2010 

Because it is a name of the product. No matter of what is made of, it will be called Ketchup. It is an internantional product. There are different brands of Ketchup, but at the end they are labelled as Ketchup.
Here is a link for more information. Also, check what they name it in other languages.
http://en.wikipedia.org/wiki/Ketchup

12:51 Jul 24, 2010 

But why you always transliterate? :( It has a meaning.