CHALLAH HAS BEEN TAKEN

 

Answer: 

Callah, also known as "kallah bread", is technically not kosher.  Also, the phase "Challah has been taken" should apparently and historically be associated with a kidnapping according to some historical documents, and it is the non-kosher consumption of breads and other leavened bread products which are forbidden during Passover season.

Nonetheless, the definition of the word "kosher" has apparently changed over many centuries, and, subsequently, a large number of Jews, consume Callah  year-round; especially on Shabbat.  

Further, it is the consumption of flattened bread, which is technically healthier for one who maintains a kosher for health lifestyle; based on basic concepts of human digestion 

Furthermore, no traditional bread items are technically Kosher, and are forbidden on Passover; according to how one can interpret Jewish cultural traditions surrounding the concept of what is considered to be kosher for passover.

In summary, traditional bread commonly made to raise through the use of yeast, can be  considered to not be kosher according to historical documents pertaining to the evolution of the word "Kosher".