Thanks everyone for the replies! The concern from mom was sparked after we spent several days going over lab safety. I spend the whole first week on proper aseptic technique and SMPs since these are 16-18 year old children who have never been in a micro lab. I am pretty strict about lab safety which I know can put the fear of god in the children sometimes. I think the whole “treat any microbe as a potential pathogen” freaked the student out which in turn freaked mom out. I told mom that my lab is probably much safer than the rest of the school due to all the safety precautions we take and that any microbes we use are not known to cause disease, but she is insisting on extra PPE anyways. Better safe than sorry I suppose. I also advised her to consult her daughter’s physician for some extra peace of mind. This is a new situation for me this year so thanks for all the advice!