The Effect of Time and Temperature on the Growth of Bacteria in Soy Bean Oil

The premise of this experiment was to test if more bacteria colonies grew in soybean oil in a fryer over time when incubated at different temperatures. Potatoes were fried in soybean oil in each temperature overnight for a period of five days. Each day, a sample of soybean oil was collected and spread on ten petri dishes. These dishes were separated into groups of five and placed in two different incubators, one set at 37C and one set at 25C. After incubating overnight, the petri dishes were removed and the number of colonies of bacteria in each dish was counted. To analyze the data, five two sample t-tests were performed and descriptive analysis was given. The two sample t-tests were used to test the significance of the differences of means from two random samples of independent populations. A two sample t-test was performed for each day and the two populations were the two temperatures. The descriptive analysis showed the trend of data in each temperature of the period of five days.

The results of the experiment are inconclusive due to a lack of data. To correctly perform the two sample t-test, thirty trials for each population need to be obtained. The researchers only performed five. This was because in the beginning of the experiment a different statistical analysis that did not require many trials was going to be performed. However, while performing the experiment it was discovered that a different statistical analysis was needed. The tests were still performed and showed that there was a difference in the number of bacteria colonies at each temperature but the day did not affect it.

Research Done By:

Hannah Mico
Lake Shore High School

Patricia Rempala
Lake Shore High School