1. By: Sapna Seth, Julia Feldman, & Ashley Elmore
The Effect of Different Brand Name Disinfectants on the Amount of Bacteria Killed
By: Sapna Seth, Julia Feldman, & Ashley Elmore

2. Which brand name disinfectant (CloroxⓇ, LysolⓇ, or Scrubbing BubblesⓇ) is most effective at killing bacteria?
Null Hypothesis: There is no statistically significant difference in the amount of bacteria killed (zone of inhibition) when bacteria comes in contact with Lysol® Power & Free Bathroom Cleaner vs. Disinfecting Scrubbing Bubbles® Bathroom Cleaner vs. Clorox® Disinfecting Bathroom Cleaner vs. deionized water.

3. Alternative Hypothesis 1
If Escherichia coli K-12 is disinfected with different
brand name disinfectants, then the Lysol® Power
& Free Bathroom Cleaner will be the most effective
at killing bacteria, because it contains hydrogen
peroxide, a high level disinfectant, which means it will
kill all of the bacteria except for a few bacterial spores
by denaturing their proteins and lipids.

4. Alternative Hypothesis 2
If Escherichia coli K-12 is disinfected with
different brand name disinfectants, then
Clorox® Disinfecting Bathroom Cleaner
will be the most effective at killing bacteria,
because it contains two variations of quaternary
ammonium compounds that will damage the
bacteria’s cell membranes by denaturing their proteins and disrupting their permeability.

5. Alternative Hypothesis 3
If Escherichia coli K-12 is disinfected with different brand name disinfectants, then Disinfecting Scrubbing Bubbles® Bathroom Cleaner will be the most effective at killing bacteria, because it contains four variations of quaternary ammonium compounds that will damage the bacteria’s cell membranes by denaturing their proteins and disrupting their permeability.

6. Alternative Hypothesis 4
If Escherichia coli K-12 is disinfected with different brand name disinfectants, then deionized water will be the most effective at killing bacteria, because the deionized water would act as a hypotonic solution. There would be more water around the bacteria than inside, and water would flood into the bacteria until they burst, damaging the bacteria.

7. Summary Independent Variable: Brand of Disinfectant Used
Dependent Variable: Amount of Bacteria Killed
Quantitative Data
ANOVA Test

8. Bacteria Bacteria are prokaryotic organisms.
Escherichia coli K-12 is the type of bacteria used in this experiment.
Escherichia coli K-12 is from the Enterobacteriaceae family.

9. Disinfectants Disinfectants kill bacteria by: Damaging cell membrane
Disinfectants are substances, such as heat or chemical solutions, that are used to control the growth of microorganisms.
Disinfectants kill bacteria by:
Damaging cell membrane
Denaturing enzymes and other proteins
Damaging DNA

10. Chemicals In Disinfecting Scrubbing Bubbles® there is:
Alkyl dimethyl benzyl ammonium fecting Bathroom Cleaner there is:
n-Alkyl dimethylbenzyl ammonium chloride
n-Alkyl ethylbenzyl ammonium chloride
In Lysol® Power & Free Bathroom Cleaner there is:
Hydrogen peroxide
C10 Ethoxylated Alcohol

11. Purpose of Experiment
Scrubbing Bubbles®, Clorox®, and Lysol® brands all claim that their products kill 99.9% of bacteria.
This experiment was conducted in order to see which disinfectant is actually able to kill the most bacteria.

12. Materials & Procedure s. Incubate petri dishes for four days at 37°C.
Measure zones of inhibition (mm).
Properly disinfect materials.

14. Results

16. Conclusion
Alternative hypothesis 3, which states, “If Escherichia coli K-12 is disinfected with different brand name disinfectants, then Disinfecting Scrubbing Bubbles® Bathroom Cleaner will be the most effective at killing bacteria, because it contains four variations of quaternary ammonium compounds that will damage the bacteria’s cell membranes by denaturing their proteins and disrupting their permeability.” is supported.

17. Conclusion (Cont.)
Scrubbing Bubbles® is the most effective brand name disinfectant.
Scrubbing Bubbles® damaged the bacteria’s membrane.
The null hypothesis can be rejected, because the overall p-value is , which is less than 0.05.
Clorox® and Scrubbing Bubbles® are not statistically significant, since their p-value is greater than 0.05.

18. Experimental Errors and Unusual Results
There was excess disinfectant around some of the chads.
All of the zones of inhibition collected for deionized water were approximately 0mm except for one zone of inhibition which was 3mm.

19. Further Research Questions
Is Disinfecting Scrubbing Bubbles® able to effectively kill gram positive bacteria?
Which non-brand name disinfectant is most effective at killing bacteria?
What is the effect of different brand name disinfectants on another common bacteria other than E. coli K-12?

20. Work Cited
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22. Work Cited
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