The Effects of Fructose and Stevia Natural Sweetener on the Colony Growth of Streptococcus salivarius

The purpose of the experiment was to determine which variable, Stevia natural sweetener or fructose, would have the greatest effect on the amount of colonies of Streptococcus salivarius cultivated over a 48-hour period.  Three different types of agar were used in which the bacterium were cultivated: pure agar, agar with fructose, and agar with Stevia.  There were forty trials run for each type of agar and the cultivated colonies were counted.  The original hypothesis of the experiment which stated that the Streptococcus salivarius cultivated in agar with fructose would have the greatest number of colonies was rejected.  Two separate two-sample t tests were conducted for data analysis along with box plots to compare the collected data.  The obtained data showed that there was almost no difference between the amounts of colonies cultivated in the pure agar and in the fructose, but the colonies cultivated in the agar with Stevia had a significantly larger amount of colonies.  Dental caries is one of the most common disorders and with the introduction of new foods, sweeteners, and alternatives, understanding how these things interact with the bacteria that cause dental caries will help in the maintenance of those pearly white smiles.

Research Done By:

J Bushaw
Lakeview High School

Paulina Starostka
Cousino High School