Oversight of sin

Hi,

One may not appoint a mashgiach [kashrut supervisor] for a food production facility in which a particular process requires a Jew to violate Jewish law, even where the end result will be a kosher product. Assigning a mashgiach there would give the false impression of approving the violation of Jewish law, and so violate the lifnei iver prohibition against causing the blind to stumble.

(Rav Moshe Feinstein, Igrot Moshe Yoreh Deah 2:41)

Have a great day,
Mordechai