Do dishwashing detergents require kosher supervision?
It is generally assumed that dishwashing detergents are not edible entities, and halachically they do not have a non-kosher status, even if they contain non-kosher ingredients, as is often the case. Nonetheless, some Poskim maintain that it has been the established minhag Yisroel (Jewish custom) to use kosher detergents on plates, pots and utensils that come in contact with food. An OU on a detergent insures the kosher status of that product. That said, if one used non-certified dishwashing detergent, Bidieved (after the fact), the kosher status of the utensils would not be compromised.