Chefs planning to cook within the Jewish cultural and religious realm must remember to never mix meat and milk while also ensuring any processed or purchased ingredients have been certified kosher through supervision by a rabbi if they want to adhere to the observance of being what?
The Hebrew word "kosher" (כָּשֵׁר) literally means "fit." It's pretty much a law for Jewish people to eat kosher and respect Torah 11 and Torah 17 which gives them that law.