I have seen many articles in the past claiming that the sink faucet is the dirtiest area in your kitchen, and I wanted to see what bacteria grow there. The sink faucet is a moist environment typically, however it is not consistent temperature wise. A sink faucet can be exposed to cold water, room temperature air, or hot water meaning that any bacteria growing on the faucet would have to be able to withstand constant temperature change.
As for the handle at my lab station, I figured it was an object that everyone who goes into that lab room has touched, and probably isn't washed as often as the table tops are. I predicted that any bacteria growing on the handle would grow best in a room temperature area, or the 27° C petri dish, since the handle is in a room with that temperature.
Next, my mouth. Being at body temperature, and moist, it is the perfect habitat for bacteria. I expected that my mouth would would have many bacteria in it, considering bacteria can be inhaled, or on our food meaning that there would always be uncontrolled travel of bacteria into the mouth.
Lastly the bottle of expired lemon juice. This sample was either going to to be grow a lot of bacteria or none at all. Although, there was some type of mold at the bottom of the bottle, I was worried about the acidity of the lemon juice not producing any bacteria.
DAY 0:
On 4/4/16 I set up the petri dishes with the samples listed above. This is a picture before any incubation occurred. The dish on the left is the one that was incubated at 37° C, while the one on the right was incubated at 27° C.
Day 2:
After a day of incubating this was my results on 4/6/16. The 27° C dish on the right produced no bacteria except in the area where my mouth was swabbed. While the 37° C dish on the left produced bacteria in both the mouth area and the sink faucet area.
Day 7:
After incubating for week on 4/11/16, these were my results. I was slightly surprised at this point that the sink faucet grew so much bacteria. Especially on the the room temperature plate on the right, which had no growth on day 2. I was also surprised when their was one colony on the 37° C plate in the handle area, right by the label on the left.
When comparing my results with the rest of my lab group I noticed that I was the only one that did not have any growth from the lemon juice. And the other member in my group that also tested their mouth, had a dish with many different colonies of different bacteria, while my plate only produced a white circular colony.
Base on the Academic site I believe that the bacteria that I swabbed from the sink faucet are Micrococcus luteus. However, the bacteria in the mouth area is slightly harder to identify. My best guess is that the mouth bacteria is Staphylococcus epidermidi, due to the fact that the bacteria in the room temperature plate is almost the same color as the agar.
First off, what a nicely written blog post. I loved how you explained your predictions. And what a great idea to swab the sink faucet. I am kind of glad to see that there weren't that many bacteria growing on the sink handle, probably because it is a really uncontrolled environment and if I were a bacteria I would want a relatively stable environment. It seems that the white, circular bacterial colony that you found in your mouth is similar to the one I found under my armpits. But I did not have the lawn growth that you observed on the 2nd day.
ReplyDeleteThe sink is the are with the yellow bacteria and it produced a lot of bacteria in after a week. Maybe weren't was a typo, but I just want to clarify, there are bacteria there.
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