1. The Effects of Laundry Detergent on Microbial Flora
Brian Sproule
Pittsburgh Central Catholic
Grade 9

2. Laundry Detergent Common household item
Alternative to using soap to wash clothes
Made up of builders, alkylbenzenesulfonate surfactants, bleaches, and enzymes.

3. Builders Frequently known as water softeners
Made up of: sodium carbonate, complexation agents, soap, and zeolites
Zeolites are minerals used as commercial catalysts
Most common builder is Sodium Triphosphate
Inorganic compound found in modern industrial products

4. Bleaches Common ingredient found in detergent
Used to target stains of vegetable origin
Chlorophyll, Anthocyanin Dyes, Tannins, Humic Acids, and Carotenoid Pigments
Require Enzymes to aid in removing stains

5. Enzymes in Detergent Fundamental in the cleaning power of detergent
The enzymes remove recalcitrant stains made up of proteins, fats, and carbohydrates
Each specific enzyme targets a specific type of stain
Fats, Lipases
Carbohydrates, Amylases
Proteins, Protease

6. Past Studies
Detergent had a negative effect on survivorship of bacteria
Varied with current experiment:
Used Staph instead of Escherichia coli
Powdered detergent
Different concentrations

7. Escherichia coli Extremely prevalent form of
bacteria found in a range of
environments
Gram negative, rod shaped bacteria
Reproduces rapidly
Mostly harmless or beneficial, but some strands are pathogenic and cause food poisoning
Common mammalian intestinal symbiont

8. Purpose
Purpose-
Determine the effects of Tide Laundry Detergent on survivorship of Escherichia coli.

9. Hypotheses Alternative Hypothesis-
As concentration of detergent increases, the number of colonies will decrease.
Null Hypothesis-
The laundry detergent will have no effect on the number of colonies.

10. Materials Tide Laundry Detergent Micropipettes Sterile Pipet Tips
Test Tubes
Test Tube Racks
Luria Broth Agar Plates (1% Tryptone,
0.5% Yeast Extract, 1% Sodium Chloride)
Spreader Bars
Ethanol Flame
Ethanol
Safety Goggles
Incubator (37° Celsius)
Sharpie
Vortexer
Escherichia coli
Sterile Dilution Fluid (100mM KH2PO, 100mM K2HPO4, 1m NaCl)

11. Procedure (Liquid Exposure)
E. coli was grown until a density of 50 klett spectrophotometer density was reached. This was approximately 8^5 cells/mL.
The culture was diluted in sterile dilution fluid to a concentration of approximately 10^5 cells/mL.
Pipetted appropriate amounts of Tide Laundry Detergent and Sterile Dilution Fluid into 4 appropriate test tubes
Vortexed each test tube to obtain mixed solution
Added indicated amount of Escherichia coli to each individual test tube. Solution incubated at room temperature for fifteen minutes

12. Procedure (Liquid Exposure)
Pipetted 0.1mL from each test tube (0.4 mL’s from each tube) on to the LB agar plates. A new pipet was used for the sterile dilution fluid, detergent, and E. coli.
Spread solution evenly along the plate by using sterile spreader bars. Each spreader bar was sterilized in an ethanol flame before and after use. A total of 24 liquid exposure plates were done in total
Incubated plates at 37° Celsius for 24 hours
The number of E. coli colonies were counted and recorded

13. Liquid Exposure Results
P Value:
Significant

14. Dunnett’s Test Concentration T Value T crit. Value Conclusion 0.01%
1.14
3.1
Not Significant
0.10%
3.6
Significant 1%
4.9

15. Procedure (Infusions)
Stock Solution was made up of 10% detergent and 90% sterile dilution fluid
Pipetted 200ul of sterile dilution fluid onto four plates. Pipetted 20ul of the stock solution and 180ul of sterile dilution fluid onto four plates. Pipetted 200ul of pure stock solution onto four plates (Total of 12 Plates)
Allowed plates to incubate for one hour at 37° Celsius
Pipetted .1ml of the control solution (9.9ml sterile dilution fluid and .1ml E. coli) onto each plate

16. Procedure (Infusions)
Incubated plates for one day at 37° Celsius
Plates were taken out and the number of colonies were counted and recorded

17. Infusions Results
P Value:
Not Significant

18. Conclusion Liquid Exposure Infusions
Detergent had a strong antimicrobial effect on the e. coli.
Reject null hypothesis for all concentrations
Infusions
No noticeable antimicrobial effects were found in the infusion process
Failed to reject null hypothesis

19. Limitations Only one form of bacteria was being tested
Plating, vortexing, pipetting, exposure times were slightly unsynchronized
Limited amounts of concentrations
Only one exposure time

20. Future Experimentation
Could test on many different types of bacteria
More precise plating and incubating techniques
Varying exposure times
Synergistic effects with other chemicals
Different concentrations of detergent

21. Works Cited
Fiorillo, Doreen E. "The Effect of Detergent on Bacteria." EHow. Demand Media, n.d. Web. 30 Dec
"Gram Stain Technique." Gram Stain Technique. N.p., n.d. Web. 30 Dec
Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 21 Dec Web. 30 Dec
"E. Coli Bacteria Infection Symptoms, Causes, Treatments." WebMD. WebMD, n.d. Web. 30 Dec
"E. Coli – the Biotech Bacterium | Biotech Learning Hub." Biotechnology Learning Hub RSS. N.p., n.d. Web. 30 Dec
"Gram-negative." MedicineNet. N.p., n.d. Web. 30 Dec. 2015
Berlow, Lawrence. "Laundry Detergent." Encyclopedia.com. HighBeam Research, 01 Jan Web. 30 Dec
"Sodium Tripolyphosphate." Sodium Tripolyphosphate. N.p., n.d. Web. 30 Dec
"Enzymes in Laundry Detergents." Enzymes in Laundry Detergents. N.p., n.d. Web. 30 Dec
"Zeolites." ASDN. N.p., n.d. Web. 30 Dec

22. ANOVA Liquid Exposure

23. ANOVA (Infusions)