Testing Variables of Foods, Films, Antimicrobials and Surfaces Affecting Transfer and/or Survival of Bacteria

Title: Bacterial transfer:  Sharing cups? Thanks again! Transfer on plastic cups

Team Mentor:

Dr. Paul Dawson, Professor
Dept. Food Science and Human Nutrition

Student team members: Hayley Thorson, Kelly Hooton, Justin Runey, David Hughes, Sally Foster, Melissa Roskosky, Sutton Fain-Schwartz, and Danielle Lynn

Abstract:: As a college student, it is not uncommon to share a drinking cup without thinking twice about it. Bacterial transfer is a concern, so as curious students, our Creative Inquiry team examined the bacterial transfer onto and into plastic drinking cups. Two experiments were performed to (1) test bacterial transfer to the rim of a plastic drinking cup, and (2) test residual bacteria in the liquid that was consumed from the cup. Bacteria were recovered from cups by placing them into a sterile bag containing sterile water then rinsing and “scrubbing” from the outside of the bag. Bacteria were enumerated by taking 1 ml from the recovery bag and serially diluting then plating on nutrient agar. The results for both types of transfer showed higher bacterial populations on cups exposed to drinking compared to those where no drinking occurred.  However, there was more bacterial transfer on the rim of the plastic cup than the liquid inside the cup.