Bacterial Growth on Processed Eggshells (US) vs Unprocessed Eggshells (UK)

The purpose of this project was to determine if there is a difference between the bacterial growth on processed egg-shells and unprocessed egg-shells that haven’t been through any type of disinfection process. This is important because people, everyday, eat eggs. The hypothesis was that the processed egg-shells would show more bacterial growth compared to the unprocessed egg-shells because they have been stripped of their cuticle. The egg-shells were tested by dipping them in a bacterial broth which was a mixture of tryptic soy broth and micrococcus luteus. They dried for twenty-five to thirty minutes and then were swabbed. The eggs were swabbed using sterile cotton swabs dipped in sterile water. The swabs were then used to streak petri dishes in a zigzag motion and were set on the top of an incubator (set to 25°C), to be incubated at room temperature. After about 128 hours, the petri dishes were taken off of the incubator and pictures were taken of each. Imagej software was used to count the colonies of micrococcus luteus on each petri dish. The data was analyzed in Google Sheets where a t-Test was run (using the XLMiner add-on) to tell if there was a significant difference in the amount of bacteria on the unprocessed versus processed egg-shells. These results concluded that our hypothesis was true; the processed egg-shells showed more micrococcus luteus. However, the unprocessed eggshells showed more mold and different bacteria. Future research could be done to test what types of potentially harmful bacteria are found on unprocessed egg-shells, and other ways to disinfect eggshells without stripping them of their cuticle