Icky Sticky Fingers #3: I ran into a couple of problems with this version, however I think I can adjust a few things to make it work. The issues I ran into are summarized below:
While the nutrient agar firmed up beautifully in the refrigerator, it melted when I put it out in the garage. I think the agar could use a little more gelatin so that it remains firm at warmer temperatures.
- Since bacteria grow well at body temperature (~98 degrees), I thought putting it in the garage would be the best place in the house (~100 degrees). It was way too warm in there and the gelatin melted. I decided to put it in the laundry room (much cooler, but the warmest place in our house...about 80 degrees). Most of the petri dishes firmed back up nicely.
Results: So far, I am noticing some really nice bacterial growth on all of the dishes, except for the control (yay!). If you look carefully at the top two photos, you'll notice the the dirty hands petri dishes have the most bacterial growth (you can't see the paper towel pattern through the media). While both clean hand petri dishes have bacterial growth, it is much less than the dirty hand petri dishes. The control petri dish was not touched at all and has no growth at all. WooHoo! Success! And such a cheap and easy experiment!
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