IntroductionThree bacteria were studied during this experiment. Staphylococcus is a type of bacteria often found on the bodies of humans and animals. It is found on the skin and hair, as well as in the nose and throat. Staph can cause food poisoning when exposed to food and contaminated because the food is not properly refrigerated. (Food Safety) These bacteria are Gram-positive with a spherical shape that often clump together, just like grapes. (Bacteriology) The only way to kill these bacteria is by cooking and pasteurization. Bacillus cereus is a type of bacterium that produces toxins that can cause two types of diseases. One type causes diarrhea and the other causes nausea and vomiting. These bacteria are found in foods and multiply rapidly at room temperature. (Food Safety) Bacillus cereus is also Gram-positive and is rod-shaped and very large. It can easily spread to many types of foods such as plants, eggs, meat and dairy products. (MicrobeWiki) Escherichia coli is a bacterium found in the gastrointestinal tract and capable of producing a toxin that can cause serious infections. This bacterium can be acquired by consuming contaminated food or water. (Central European) The E. coli is often used to help the body break down and digest certain foods. It becomes dangerous when the bacteria pass from the intestine into the blood. (Kids Health) Escherichia coli, unlike any other bacterium studied, is Gram-negative. It is also shaped like a stick and is medium in size. (Mansfield)This experiment also tested four different antibiotics with these bacteria. Oxacillin is an antibiotic commonly known for treating staph infections. This antibiotic... it's half paper... it won't move when the petri dishes are turned upside down during incubation. After each disk was placed in the Petri dish and looked like the one in Figure 1, the lid needed to be closed. It was very important to check and make sure that each petri dish was labeled with the correct antibiotic. Once all the antibiotics were placed in each Petri dish and sealed, one student from each group had to incubate them upside down in the incubator. After 24 hours, one student from each group was asked to return to the lab to check their group's Petri dishes. The size of the circle formed by the antibiotics around the bacteria is recorded in the table. After completing the data, each plate needed to be placed in a tray for autoclaving. The most important thing to remember was to wash your hands and everything that touched the dishes.