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What temperature will kill the most bacteria? Hypothesis:Because water freezes at 0 degrees Celsius, and boils at 100 degrees Celsius, it is unlikely that bacteria will survive these conditions for more than a short time. Procedure:
Non-pathogenic Escherichia coli will be placed in sterilized jar
lids. The lids will be placed on a water bath for 20 minutes.
One water bath will be at 100C and another bath at 50C. One lid will
be kept at room temperature for 20 minutes. Another lid will be
placed in a freezer for 20 minutes. After 20 minutes each lid will
be swabbed and wiped onto nutrient agar. The petri dishes with the
agar will sit undisturbed at room temperature for several days.
Bacteria growth on the agar will be measured. |
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Conclusion: Exposing non-pathogenic e-coli to 100C for 20 minutes killed the bacteria. Exposure to freezing temperatures for 20 minutes actually made the bacteria grow better when brought back to room temperature. Future research could include exposing the bacteria to other temperatures just below the boiling point of water to determine what temperature is no longer effective at killing it. Also, adding the bacteria to a food such as mayonnaise or hamburger may determine if chemicals in the food influence bacteria growth or death at different temperatures. Biblical Application:Second Thessalonians 3:3 says "For the Lord is faithful... and will protect you from all evil." Just like insulation protects us from the cold, so also will God protect us from all evil. |
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300 Cromwell Street, Phillipsburg, New Jersey 08865 |
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1st Place, 6th Life Science, PCA Science Fair