A long read, but worth reading if you are in this domain: http://msdn.microsoft.com/en-us/library/windows/desktop/aa365247%28v=vs.85%29.aspx.
Manage Food Service Staff. Food and beverage managers are often responsible for recruiting, hiring, training, evaluating and terminating food service staff members. Personnel management of restaurant staff requires experience as well as interpersonal skills.
Why you want to know: This just means that the caterer, in addition to food preparation, will handle everything from the table settings to bar service and cleanup. What's included depends on the catering company and the packages they offer. If it isn't full service, you'll have to find (and pay) additional staff.