Q: What if a person was to work in a capacity other than cooking in a kitchen, say mixing cold meat and milk together?

A: Poiskim recommend avoiding being hired as a chef in a non-kosher kitchen that prepares food even if only for Gentiles, as he may partake from it while working or may cook meat and milk together. (Yabia Omer Y.D. 4,6 – Yalkut Yosef, Isur Veheter 4,6). Mixing cold meat and milk together without cooking it, is not prohibited, even if it is left for more than twenty four hours.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a