Bottomline is - food should not be eaten in any lab by any occupant - by students or employees/volunteers!  This is clearly stated as a faux pas in legal safety standards and better professional safety practices.

I do mock-OSHA inspections of laboratories and also serve as an expert witness in law suits for parents whose child has been injured in school science labs.  In inspection I noticed a small table in back of a chem. lab at a high school with a sign on it - "Chemical Free - Only Eat Food At This Table!"   I asked the teacher if he ever heard of the term "cross contamination?"  I noticed book bags on the lab desk tops.  The same book bags were then brought over to the "Chemical Free" table.  First of all - book bags don't belong on lab desks..  Secondly - any chemical residue is then dragged over to the - oh wait a minute - the "Chemical Free - Only Eat At This Table!"  No matter how you have the lab cleaned - it never forgets the hazardous chemicals used previously.

If a student for medical reasons (under direction of a school nurse or private physician) needs to eat during a lab period - fine - have them leave the lab and eat elsewhere that is approved and supervised - then return.  Science teachers, their supervisors and building administrators have too much liability exposure should a student be exposed to the products of cross contamination while eating in the lab.  More importantly - the student could become seriously ill!

Hope this helps -

Dr. Ken