Method

1.      Mix ¼ t agar with 30mLs of hot water and stir in the container. Put the mixture in the microwave for 2 minutes and dissolve the agar. When handling the agar and petri dishes, always wear disposable gloves and sanitize your hands. Leave the mixture to cool for 5 minutes. This makes enough agar solution for 1 petri dish.

2.     Make 7 exact solutions for 7 petri dishes. Pour each mixture into one side or lid of each petri dish. Cover the petri dishes with plastic wrap and let the agar solution harden for 1 hour.

3.     Collect bacteria on the end of 1 cotton tip. First, sanitize your hands with hand sanitizer. Wipe the end of each cotton tip on a table in the cafes, making a total of 6 swabs. Store each tip in a clean zip-lock bag that is labeled with the restaurant’s name. Keep 1 clean, unused swab aside and store it also in a bag labeled with ‘Control’. This tip will be your control, to make sure that each tip and the agar solution was clean and without any bacteria to begin with.

4.     Take the plastic wrap off of each petri dish and lightly rub a tip into the agar. Close the petri dishes and tape them up around the edges to avoid escaping bacteria. Label each dish with the café names you collected from and label the ‘Control’ using the markers.

5.      Place the petri dishes in a warm, dark place to let the bacteria grow. I left them in my cupboard, which is dark. Do not put them in a place of temperatures exceeding 37ºC. Leave the petri dishes in the same place for 2 weeks. Record observations and photograph the dishes at 6:30pm every day.

6.     One the experiment is finished, the petri dishes need to be correctly disposed of. Keeping the dishes securely closed, pour bleach over them to avoid contamination. Put the petri dishes into a plastic bag and put them into a rubbish bin.