Date of Award


Degree Name

Biological Sciences


College of Science

Type of Degree


Document Type


First Advisor

Dr. Frank Binder

Second Advisor

Dr. Marcia Harrison

Third Advisor

Dr. Charles Somerville


The United States Pharmacopoeia (USP) Microbial Limits Test and Preservative Effectiveness Test were validated and completed on an alcohol-free mouthwash using standard USP recommended microorganisms and selected organisms isolated from the manufacturing environment. The microbial limits test using environmental isolates was found equivalent to the USP Microbial Limits Test currently used for release of the product. The preservative effectiveness test was performed to determine the efficacy of the parabens system against environmental isolates compared to those recommended in the USP test. In both tests Pseudomonas aeruginosa isolates exhibited resistance to the preservative system. All other isolates failed to grow after week one. Temperature studies conducted with environmental isolates to evaluate sanitation procedures for manufacturing indicated organisms exposed to 70˚C for ten minutes resulted in at least a seven log reduction in number. Environmental isolates exposed to 60˚C and 65˚C were found to survive at these elevated temperatures after a ten minute exposure period.


Microbial ecology.

Microbial contamination.

Food Preservatives -- Effectiveness.

Included in

Organisms Commons