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Which type Soap Kills More Bacteria During Handwashing

regular liquid, regular bar, hand sanitizer, antibacterial liquid, antibacterial bar An experiment in better handwashing choices

Nellie Drinkard

on 16 January 2013

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Transcript of Which type Soap Kills More Bacteria During Handwashing


White, Steven. "How to Find Whether Non-Bacterial Soap Work Better Than Antibacterial Soap." eHow. Demand Media;. Inc. 19999-2012. Web. http://www.ehow.com/how_8616721_out_soap_works_better_antibacterial.html

This article was the model I used for my project. It is a project to find whether non bacterial soap works as good as antibacterial soap. There was no difference in the bacterial growth as a result of this experiment. REGULAR BAR REGULAR LIQUID AN EXPERIMENT IN BETTER HANDWASHING CHOICES ANTIBACTERIAL LIQUID ANTIBACTERIAL BAR WHICH TYPE SOAP KILLS MORE BACTERIA DURING HANDWASHING Knowing which type soap is more effective for reducing the number of bacteria can help to identify which type of soap to purchase for daily family use. This can reduce the number of diseases a person is exposed to; aid in keeping them cleaner faster, and prevent the spread of diseases to others. This experiment will attempt to answer which type of soap products kill bacteria: regular liquid, regular bar, hand sanitizer (no rinse), antibacterial liquid, or antibacterial bar. We will find out through testing which soap is most effective at killing bacteria. This information may be used to inform people how to get their best result when they do wash their hands. PURPOSE HYPOTHESIS
Does it matter if a soap is liquid or bar; if antibacterial chemicals make a difference; or whether or not water is used? At this time I am not sure of the outcome of whether there is a difference in how the type of soap affects the reduction of bacteria. My research so far shows hand washing to be important to reducing diseases.
If I create an environment to imitate bacterial growth on an unwashed hand using a contaminated substance; then wash the contaminated hand with one of the soap choice; swab the cleaned hand; swipe the swab on agar prepared petri dishes (repeating multiple times for each soap product); I will be able to compare my results; record my findings; and make to determination based on my results. BACKGROUND RESEARCH - 2

Maxine Burton, Emma Cobb, Peter Donache, Gaby Judah, Val Curtis, and Wolf-Peter Schmidt. "The Effect of Hand washing with Water or Soap on Bacterial Contamination of Hands." International Journal of Environmental Research and Public Health. January 6, 2011. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3037063

This was a study to see if washing your hands with soap and water killed more germs than washing hands with just water. Washing with water alone did reduce the amount of bacteria on hands. Soap and water took more time and killed more germs than water alone. The use of soap for hand washing was suggested. Jumaa, P.A. Hand Hygiene: Single and Complex." International Society for Infectious Diseases. January 9, 2005.
http://www.ncbi.nlm.nih.gov/pubmed/15603990 This article looks at different areas that may reduce effective handwashing and how it is important in the community for reducing disease. Regular handwashing with soap and hand drying could save the lives of millions. Hands transfer germs with direct contact. Jewelry, clothing around the wrist, fingernails, and fingernail polish, the proper use of gloves and the use of lotions are areas for future study. If people would just wash their hands it would make an impact. BACKGROUND RESEARCH - 4

Liu, Shijin, "All About Agar." Science Buddies. 2002-2013.
http://www.sciencebuddies.org/science-fair-projects/project_ideas/MicroBi_Agar.shtml Was helpful in helping my understanding of agar. Talked about the different types of agar and how they are effective in growing bacteria. Had instructions for preparation, bacteria growth, and the proper way to dispose of petri dishes. Answered question of gelatin instead of agar. BACKGROUND RESEARCH - 5

Layton, Beth M. "Disinfectants and Salmonella: A Study Showing th Effectiveness of Disinfectants Against the Bacteria Salmonella." Saint Martin's University Biology Journal. May 2006.

This article helped with how to prepare agar for the petri dishes. It was not about handwashing but how disinfectants would help stop spread of salmonella. Chose to use top of stove method to prepare agar instead of microwave. BACKGROUND RESEARCH - 6

"Handwashing : Clean Hands Save Lives." Centers for Disease Control and Prevention. January 23, 2012. http://www.cdc.gov/handwashing/

Wash your hands properly. Most diseases are transferred by not washing hands. You should have soap and clean running water when washing hands. If soap is not available; use available water. If no soap and water use alcohol based hand sanitizers. Wash hands before and after eating, taking care of the sick, using the bathroom, touching and feeding animals, and touching garbage. BACKGROUND RESEARCH - 3 Frequent handwashing has been proven to reduce the spread of infectious diseases. However many people do not wash their hands frequently. When you rub your mouth or eyes after you have not washed your hands you can provide openings for germ entry to your body, especially with the common cold. You can also infect other people when you do not wash your hands. EXPERIMENTAL DESIGN

Soap is the independent variable.
Regular liquid - regular bar - hand sanitizer (no rinse) - antibacterial liquid - antibacterial bar- unwashed

The bacterial growth in the agar prepared petri dishes will be the dependent variable. It will change based on the outcome of the experiment.

Constants will include: length of time exposed to contaminate (5 seconds), length of time washing hands (happy birthday song-twice), paper towel drying, swab hand and swipe agar, close lids, repeat for each soap, storage in dark box near heater. MATERIALS
Soap used in testing
regular liquid (r.l.) Softsoap- apricot sunshine
regular bar (r.b.)Softsoaap - coconut scrub
hand sanitizer (h.l.) Assured- Ethyl Alcohol-62 %
antibacterial liquid (a.l.) Dial- Triclosan-0.15%
antibacterial bar (a.b.) Triclosan- 0.30 %

The contaminate was made up of 2 oz spoiled yogurt; 3/4 cup spoiled milk; 1 cup rotten salad mix; blood pack from 3 lb of thawed chicken; piece of raw chicken; raw milk-egg-chicken solution; egg shells, flour from chicken coating in a solution of water from a leaky refrigerator. Mixed and sat 45 minutes at room temperature.

agar prepared petri dishes
20 grams agar - 250 ml purified water / experiment
6 petri dishes/ experiment
pressure cooker
bleach/alcohol/lysol brand cleaner
box & space heater
cotton swabs
running water PROCEDURES
Step 1 Preparation of petri dishes
.cleaned test area with Lysol disinfectant/ rinsed with bleach water 1 tbsp to quart water.
.wiped tray with alcohol and soaked 10 minutes in bleach water
.weighed 20 grams agar on scale
.measured 250 ml purified water in beaker
.poured water into a pressure cooker and brought to a boil
.sprinkled in the agar powder and stirred it for 60 seconds
.placed the lid on pressure cooker brought to boil with metal
.cut off and let sit on heating element 20 minutes
. remove from heat and cool 10 minutes ( the first time it cooled 30 minutes, it was semi solid)
.pour agar into the 6 petri dishes with lids/cover immediately
.label dishes with sharpie
.arrange on tray in the order of use
.one petri dish is labeled t-test for the unwashed contaminant sample PROCEDURE -2

Step 2 - Create the contaminant
In an old disposable container combine:
2 oz of spoiled yogurt; 3/4 cup of spoiled milk; 1 cup of rotten salad mix; 1 blood pack from a thawed 3 lb chicken pack; piece of raw chicken; raw egg-milk-chicken solution, eggshells, flour from leftover chicken coating, in a base of water from a leaky refrigerator. Stir and let sit 45 minutes.

Step 3- Set handwashing area
Arrange soap in order of use. Place contaminate beside sink. Paper towels for easy use. Have tray and swabs within reach. PROCEDURES - 3

Step 4- Begin the experiment
.subject places hand into contaminant solution for 5 sec (1001-1005 count)
.hand is swabbed for the test petri dish
.test petri dish is swiped with swab replace lid
.rinse off hands start 5 different soap tests
.contaminate hands 5 seconds
.wash hands (sing "happy birthday to you" twice for time)
.dry hands
.swab hand with fresh swab
.swipe correct petri dish replace lid
.when completed- clean area up
.tape petri dishes keep on tray
.place tray in a box near a heater ( for a dark warm area)

Step 5- Check and record progress every 24 hours. RESULTS

After 72 hours, there has been no bacterial growth in the petri dishes. As a result of this experiment no evidence has surfaced to show that one soap is more effective at killing bacteria.

Many people choose to skip handwashing or not take the time to wash longer, knowing which soap would kill more germs may help in more effective handwashing. Based on the lack of data at this time. I cannot give a soap choice for faster handcleaning.

This does not supports my purpose to help families make more effective soap choices for and reduce the potential for spreading disease.

Based on the articles in my research, at minimum, people should be encouraged to wash their hands. This would reduce the spread of diseases. CONCLUSIONS

After 72 hours of observation, no bacteria had grown in any of the petri dishes. The results neither support or disprove the hypothesis. The results have not matched the experiments I read about in my background research. It is possible that enough time has not passed for the bacteria to start growing. If not, there may have been a problem with the agar solution.

There were actually two tests conducted 12 hours apart to see if this experiment could be duplicated. ( the contaminant had not been thrown out.) In the second test the agar solution was cooled 10 minutes instead of 30 minutes. It was more liquid instead of semi solid when poured into the dishes.

At this time neither sample has any bacterial growth. In the future, I would allow more time to check for results. Maybe there is be a faster way to check for the presence of bacteria. BIBLIOGRAPHY

Burton, Maxine, Emma Cobb, Peter Donache, Gaby Judah, Val Curtis, and Wolfe-Peter Schmidt. "the Effect of Handwashing with Water on Soap on Bacterial Contamination of Hands." International Journal of Environmental Research and Public health." january 6, 2011. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC30370
"Handwashing: Clean Hands Save Lives." Center for Disease Control and Prevention. January 23, 2013. http://www.cdc.gov/handwashing/
Jumaa, P.A. "Hand Hygiene: Simple and Complex." International Society for Infectious Diseases. January 9, 2005. http://www.ncbi.nlm.gov/pubmed/15603990
Layton, Beth M. "Disinfectants and Salmonella: A Study Showing the Effectiveness of Disinfectants Against the Bacteria Salmonella." Saint Martin's University Biology Journal. May 2006. http://homepages.stmartin.edu/fac_staff/moloney/website/sum%20journal/layton%202006.pdf

Lui, Shijun. "All About Agar." Science Buddies. 2002-2013. http://www.sciencebuddies.org/science-fair-projects/project_ideas/Microbi_Agar.shtml
White,Steven. "How to find out Whether Non-Bacterial Soap Works Better Than Antibacterial Soap ." eHow. Demand Media, Inc.. 1999-2012. http://www.ehow.com_8616721_out_soap_works_better_antibacterial.html HAND SANITIZER DATA ANALYSIS
No results after 72 hours-
Comparison samples:
24hr 48hr 72hr
unwashed test
regular liquid
regular bar
hand sanitizer (no rinse)
antibacterial liquid
antibacterial bar Mark Drinkard
8th Grade
Mr. Stanley Hodges
agar prep -1 weighing powder agar prep -2 add water
agar prep -3 stir 1 minute handwashing 1 contaminate handwashing 3 swab hand handwashing 2 wash hands handwashing 4 swipe agar handwashing 5 agar dishes soap
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