Why you need insurance:
There is a huge liability with cooking as a personal or private chef (fires, explosions, sharp objects, physical damages), which can be a liability in various ways.
There is also the physical hazard of people choking (bones in the food), allergies, food sensitivities.
Overall you need to keep everyone safe.
Personal Chef Associations:
Joining one of these associations helps establish a sense of trust and comfortability with a client. However, many of these corporations are very outdated and not completely user friendly.
You need a liquor license in order to serve alcohol, or you can have insurance to covers serving alcohol. You can get RAMP certified which proves that you can responsibly serve alcohol and check ID. However, the client still has to be responsible for buying the alcohol .
Serving people alcohol in their own home is still your liability.
A certificate of insurance is used to insure a party. This ensures that if something goes wrong the people are also covered under your insurance.