The Yogurt! and the Frozen Environmental sample!

Welcome back! As you can see by our title, the yogurt was a success!  Although, some people wouldn't say so!  Let's see what we found!

The Yogurt:

From left to right: The yogurt prepared with Kefir, The yogurt prepared with a preexisting yogurt with active cultures.

Both methods resulted in fermentation: yielding yogurt.  The general consensus was that the yogurt prepared with Kefir had a more natural (slightly sweet) taste, and the yogurt prepared with the active cultures was very tart.  If you are wondering what happened to the control, it curdled.  Nobody was able, or willing, to taste the milk product.

Yogurt results when the active cultures of bacteria ferment the milk!!

UV Light:
Personal Sample:

From left to right: Bacteria "F" (ours) and Bacteria "K."

Growth was prominent on both the UV exposed and the controlled portions of this plate.  This was evident in the majority of the class's samples.  We concluded that this was a result of experimental error due to inadequate exposure to the UV light.  With longer exposure time, we believe that the growth of the bacteria exposed to UV light would be affected.

Steripen Water Sample

From left to right: control bacteria sample, UV light (Steripen) treated sample

As evident from the picture above, the Steripen can be put to good use when traveling to third-world countries.  It is very useful for treating water samples.  The UV radiation hindered the majority of bacterial growth, with only a few colonies remaining after treatment.

The Environmental Sample... REVIVED!


Recall from previous blogs that we stored a small sample of our Environmental broth before sending it away to the autoclave.  This bacteria sample was then stored at -80 degrees Celsius for approximately two months.  If the bacteria was preserved correctly, by cryoprotection, the bacteria should still grow!

After retrieving the sample from the freezer we made a streak plate of the bacteria and placed it into the 37 degree incubator.  If there is growth next class, the bacteria survived!  This was the purpose of the experiment.  This technique for saving bacteria is used by professionals in the laboratory.

Join us next time for growth!