Yogurt and UV Light!!

Today, since we had already identified our bacteria, we experimented with UV Light (how it applies to everyday clinical situations) and learned how to grow yogurt.

UV LIGHT


First, in order to test UV Radiation's effect on bacteria, we made a streak plate of our identified sample. After streaking the plate we placed the uncovered dish under a UV Light, half of it covered with an index card and the other bare to take in the radiation. The glass lid could not have been kept on because glass (and even the note card) does not allow the UV Rays to pass through. After the culture was positioned under the light we used long wave UV Light, also known as UV Light C, to radiate the bacteria sample for 30 seconds.

After radiation the sample was placed into the incubator for further inspection next lab. We conducted this experiment since UV Light is becoming a clinically acceptable method to reduce the number of microorganisms in a hospital setting. We are going to see if this UV Radiation hinders the growth of our bacteria.

STERIPEN UV LIGHT PURIFIER

The purpose of the Steripen UV Light Purifier is to reduce the amount of bacteria in drinking water, which is often used by people visiting third-world countries. We tested the capability of the Steripen to purify water mixed with bacterial cultures in our lab.

First, we mixed the bacteria (using the aseptic technique of course) with a pipet into a beaker filled with distilled water.

Dr. Joseph asked specifically for us to put in this picture -- demonstrating the older technique of mixing the bacteria and water with a manual pipet. ;)

After mixing the bacteria we sterilized a glass stirring rod with isopropyl alcohol and flame.

Although some students looked mildly frightened, there was nothing to fear. This technique is 100% effective and depending on the person performing it, 100% safe. The rod was used to make a streak plate  of the water to compare with the results of the Steripen. After isolating the bacteria without the UV Light Treatment, we treated the water with the UV Light.

After the allotted time, we created another streak plate to compare with the first. Is the bacteria gone? We'll find out next class!

MAKING YOGURT


In order to form yogurt you need milk and another probiotic substance (yogurt with active cultures or Kefir, a probiotic liquid). First, we poured milk into a bowl and placed it into the microwave for 5 minutes to boil.

It is important to let the milk boil and froth until it flows over the sides of the container. After pulling it out of the microwave, it is important to let the milk cool. In our case we let it cool to 37 degrees Celsius. Don't be surprised if a film layer appears at the top of the milk, this is the fat separating from the milk.

We then separated the milk into three cups. One was a control, one was mixed with yogurt containing active cultures, and the final was mixed with Kefir.

Then we placed these samples into the incubator until next class when we will check them for growth. Growth = Delicious Yogurt!!!

Good thing it was around lunch time, because after all this microbe cooking we sure were HUNGRY! Join us next time for food and microorganisms!