Jump to main content

Bacterial Resistant Materials and the Best Disinfectant

Abstract

If you'd rate yourself high on the bacteriophobia scale, just keep on scrolling down to the next project. Bacteria are all around us, and normally our body's defenses keep us blissfully unaware of them. If you don't mind finding out where they're lurking in your house, then you might find this project interesting.

Summary

Areas of Science
Difficulty
 
Time Required
Long (2-4 weeks)
Prerequisites
Familiarity with sterile laboratory technique is a big plus.
Material Availability
Specialty items
Cost
Average ($50 - $100)
Safety
Standard precautions for handling bacterial cultures.
Credits

Andrew Olson, Ph.D., Science Buddies

Sources

This project is based on:

Objective

The goal of this project is to determine which kitchen cleaning aid is most susceptible to contamination by bacteria, and which disinfectant method cleans most effectively.

Introduction

Bacteria are all around us, and our immune system is generally good at keeping them in check and preventing them from causing us harm. This project focuses on bacteria on ordinary kitchen cleaning aids: the sponges, dishrags, and scouring pads that you use to wash dishes. Since you usually use them with hot, soapy water, they should stay pretty clean, right? Or not?

Find out how clean your kitchen is with this project investigating the bacterial resistance of ordinary kitchen cleaning materials.

Terms and Concepts

To do this project, you should do research that enables you to understand the following terms and concepts:

Bibliography

This webpage has background information on bacterial growth. It is from an online textbook of bacteriology, which can be an excellent source of further information on bacteria:
  • Todar, K., 2002. Growth of Bacterial Populations, Todar's Online Textbook of Bacteriology, Department of Bacteriology, University of Wisconsin, Madison. Retrieved October 27, 2006.

Materials and Equipment

Disclaimer: Science Buddies participates in affiliate programs with Home Science Tools, Amazon.com, Carolina Biological, and Jameco Electronics. Proceeds from the affiliate programs help support Science Buddies, a 501(c)(3) public charity, and keep our resources free for everyone. Our top priority is student learning. If you have any comments (positive or negative) related to purchases you've made for science projects from recommendations on our site, please let us know. Write to us at scibuddy@sciencebuddies.org.

Experimental Procedure

  1. Do your background research so that you are knowledgeable about the terms, concepts, and questions.
  2. Distribute the sterile saline solution to sterile tubes (at least 2 tubes per kitchen cleaning material to be tested).
  3. Cut small samples of each kitchen cleaning aid and immerse in sterile saline solution.
  4. Label the tubes and incubate 48 hours at 37°C.
  5. You should also have at least one sterile saline tube with nothing in it as a negative control.
  6. After 48 h incubation, you will plate samples from each tube. Label a bacterial plate for each saline tube.
  7. Use a sterile bacteria loop to plate a sample from each saline tube. Flame-sterilize the loop before each use, or use disposable loops, one for each tube.
  8. Use the quadrant streaking method (see Microbiology Techniques & Troubleshooting).
  9. Wait 5 minutes for plates to dry, seal with tape, and then incubate (inverted) overnight at 37°C.
  10. Count the number of colonies in each plate and record results in your lab notebook. The plate from your sterile saline solution should have no colonies.
  11. Are you surprised at the results?
  12. Now try the different disinfecting methods on samples of one or more materials. For example:
    1. Wash with soap and water, then air dry.
    2. Air dry.
    3. Microwave.
    4. Soak in 5% bleach solution, rinse, and air dry.
  13. Cut small pieces of disinfected samples, immerse in sterile saline solution, incubate 48 hours at 37°C. Again, prepare at least 2 tubes for each disinfection method.
  14. Make sure you have at least one sterile saline tube with nothing in it as a negative control.
  15. After 48 h incubation, you will plate a sample from each saline tube. Label a bacterial plate for each saline tube.
  16. Use a sterile bacteria loop to plate a sample from each sterile tube. Flame-sterilize the loop before each use, or use disposable loops, one for each tube.
  17. Use the quadrant streaking method (see Microbiology Techniques & Troubleshooting).
  18. Wait five minutes for plates to dry, seal with tape, and then incubate (inverted) overnight at 37°C.
  19. Count the number of colonies in each plate and record the results in your lab notebook.
  20. Which disinfection method worked the best?
  21. Which disinfection method(s) worked adequately?
  22. Which disinfection method(s) did not work adequately?
icon scientific method

Ask an Expert

Do you have specific questions about your science project? Our team of volunteer scientists can help. Our Experts won't do the work for you, but they will make suggestions, offer guidance, and help you troubleshoot.

Variations

  • 3-M company makes bacteria-resistant sponges for kitchen use. Compare these sponges vs. plain sponges. Do the bacteria-resistant sponges really work?
    Photo of a package of bacteria resistant sponges made by 3M
  • Compare sponges (or dishrags) that have been used for different lengths of time (brand new, 1-week old, 2-weeks old, 1 month old). When should you throw away that old kitchen sponge?
  • Compare wooden vs. plastic cutting boards. On which type of surface do bacteria live longer? Which surface cleans up better with soap and water? Design an experiment to find out.

Careers

If you like this project, you might enjoy exploring these related careers:

Career Profile
Microorganisms (bacteria, viruses, algae, and fungi) are the most common life-forms on Earth. They help us digest nutrients; make foods like yogurt, bread, and olives; and create antibiotics. Some microbes also cause diseases. Microbiologists study the growth, structure, development, and general characteristics of microorganisms to promote health, industry, and a basic understanding of cellular functions. Read more
Career Profile
Think of all the jobs in the world that involve machinery, chemicals, toxins, radiation, loud noise, or travel to places above or below Earth's surface—all of these jobs carry an element of risk to the workers. Industrial health and safety engineers work to minimize this risk. They inspect work sites and help workers and companies understand and comply with safety laws. They use their knowledge of mechanical processes, chemistry, and human psychology and performance to anticipate… Read more
Career Profile
Many people work in environments that have obvious potential dangers, like collapses in mines, chemicals in laboratories, or machinery in factories, but there can be hazards in almost any job, like repetitive stress injuries from constant computer use or from scanning groceries. Occupational health and safety specialists identify potential hazards in a job, and then figure out ways to reduce the risks of accidents or injuries to workers or to the public. They also investigate accidents when… Read more
Career Profile
Every surgical procedure, whether minor or major, requires a team of detail-oriented professionals, including the surgical technologist. From cleaning and setting up surgical equipment to assisting the medical team, the surgical technologist helps each surgery run smoothly. Job opportunities for surgical technologists continue to grow with advances in surgical techniques and technology. Read more

News Feed on This Topic

 
, ,

Cite This Page

General citation information is provided here. Be sure to check the formatting, including capitalization, for the method you are using and update your citation, as needed.

MLA Style

Science Buddies Staff. "Bacterial Resistant Materials and the Best Disinfectant." Science Buddies, 8 June 2022, https://www.sciencebuddies.org/science-fair-projects/project-ideas/MatlSci_p017/materials-science/bacterial-resistant-materials-best-disinfectant. Accessed 3 Oct. 2022.

APA Style

Science Buddies Staff. (2022, June 8). Bacterial Resistant Materials and the Best Disinfectant. Retrieved from https://www.sciencebuddies.org/science-fair-projects/project-ideas/MatlSci_p017/materials-science/bacterial-resistant-materials-best-disinfectant


Last edit date: 2022-06-08
Top
Free science fair projects.