The certification agency employs mashgichim (rabbinic field representatives[1]) to make periodic site visits and oversee the food-production or food-service process in order to verify ongoing compliance.
Each agency typically has a "certifying rabbi" (Rav Hamachshir) who determines the exact kashrut standards to be applied and oversees their implementation.
[5] Specialty agencies endorse ethical business practices, animal welfare, and environmental awareness on the part of the food producer.
It was only in the 20th century, with the increased availability of industrially-produced food products aimed at the Jewish consumer, that independent kosher certification became a necessity.
[19] In the late 20th century, the increasing use of pre-processed ingredients – such as artificial flavorings, emulsifiers, and preservatives – further broadened the scope of kosher certification.
[20] Certification agencies regularly send mashgichim to factories in China, Thailand, and the Philippines to oversee the production of pre-processed ingredients and ensure their kosher status.
[21] Certification agencies may differ on the kosher status of foods based on the p'sak (halakhic ruling) of their rav hamakhshir (rabbinic authority).
For example, aspartame, a key ingredient in Diet Coke, is considered to be kitniyot by the Kashruth Council of Canada (COR) and therefore that agency does not give its hechsher to that product for use on Passover.
The next step is for the client to supply a list of all ingredients used in its food product and machinery (such as cleaning agents), which the certification agency will research and trace back to their sources and suppliers to verify their kosher status.
[32][33] The client must also agree to specific documentation and record-keeping systems in order to track raw ingredients coming in and processed foods going out, as well as production schedules.
[30] A food-service venue must comply with additional halakhic requirements, such as respecting the laws of Shabbat, Yom Tov, Passover, and certain Jewish fast days.
Most large certification agencies maintain a database listing "hundreds of thousands of ingredients and formulas" to provide up-to-date information to their mashgichim.
[42] If they see something suspicious or have any questions about the ingredients or production process, they immediately contacts one of the agency's rabbinic coordinators, who is the decision-maker for issues of compliance and certification.
There is generally an annual fee for the certification itself, which takes into account the number and frequency of on-site inspections by mashgichim and related administrative costs.