This past semester, students taking the second semester of general biology carried out research into how to decrease bacteria in food. These types of learning experiences, called “Course-Based Research Experiences” (CUREs), are gaining popularity as a way to give students of all backgrounds an opportunity to carry out scientific research. Science is not as clean and simple as we imagine based on media reports. Participants quickly learn this as well as the systematic exploration of a hypothesis and data analysis, a valuable skill for any field. Further, the students were able to clearly see how different conditions or practices could help them prevent foodborne illness.
First, the participants found and read previously published scientific research on how to reduce bacteria in foods. While many types of foods and conditions are addressed, there is always something left to study. The students use what they have found to create a new, untested hypothesis as a class as to how they can reduce bacteria in the foods they eat. This semester, the two hypotheses addressed by the two different class sections were, “onion and garlic can reduce bacteria on raw meat,” and “potassium permanganate and bleach combined reduce bacteria on lettuce better than bleach alone.” They then planned their experiments and tested these hypotheses over multiple experiments by quantifying bacteria before and after treatment. Both classes quickly learned that experiments (and results) rarely go as planned but learned to troubleshoot and overcome the obstacles that arose. Once they had data on the numbers of bacteria before and after treatment, they practiced analyzing data and learned about the concepts of statistics. Finally, each small group of 2-3 students wrote a report and presented it as a scientific poster during a poster session. Although the results and hypothesis would be the same as their classmates, they were able to practice presenting and to see different interpretations, explanations, limitations, and visions for data applications.
At the end of the experiments, one section was able to conclude that potassium permanganate and bleach together did a much better job of decreasing bacteria on lettuce than bleach alone. As for raw meat marinated with a mixture of crushed onion and garlic, there was a tendency to reduce bacteria, but it was not statistically significant so they could not be confident these results would repeat. Regardless, both sections visualized just how many bacteria are on the foods that we eat and learned how to make better choices to stay healthy.