The mashgiach usually works on-site, inspecting and supervising the food production process. The mashgiach general represents either a kashrut organization or a local rabbi, who ultimately decides if the food is kosher or not. In smaller communities, the certifying rabbi often acts as his own mashgiach.
In addition to the technical work of ensuring the food is kosher, a mashgiaḥ also plays a social role. Mashgichim often explain kosher rules to the Jewish and non-Jewish community. They also help promote good relationships between workers and customers.
More Kosher Vocabulary Words: Glossary of Kosher Terms