This is way too much illness that MAY be related to the boxed lunches, or other problem within the venue. Contact the local health department with known info. They will want to hear about it. Contact info for health department in city of St. Louis can be found here:
http://health.mo.gov/living/lpha/cou...LouisCity.html
They can provide you with information on how to officially report the problems/illnesses. If a number of people have contacted the venue about the illnesses, they should have already contacted the health department.