Bye Bye Bacteria

Swab 3 different surfaces in the kitchen for germs then see how many germs each surface has.Take Lysol, water vinegar Myers and spray one section of that surffices for each cleaning material then swab it again.
Leah Nelson Molly Cotter
Grade 7

Presentation

No video provided

Hypothesis

Hypothesis:

We think that vinegar water will kill the most germs because vinegar is  acid and acids tend to kill a lot of organisms.

 

Research

Background Research :

  •  

  • Bacteria normally found in the kitchen:

     

    Salmonella

    Salmonella is one type of bacteria found in food poisoning, like raw meats and eggs. It is dangerous to mostly infants and the elderly, otherwise most people can get over it themselves.

     

    Shigella

    Shigella bacteria is caused when you drink dirty and not filtered water or when you touch something with many germs and touch your mouth. It is common to children under 5.

    Campylobacter                                          

    Campylobacter is a type of bacteria that can cause food poisoning, such as salmonella but can be found in any contaminated foods. Symptoms start to appear in 2-5 days.

     

    Norovirus                                                     

    Norovirus is the most dangerous of foodborne illnesses and is highly contagious. It can come from contaminated food or water that has touched a contaminated surface.

    What germs does Lysol kill? 

    Lysol kills microorganisms including Salmonella, Choleraesuis, Staphylococcus and Shigella. 

    What germs does Vinegar kill?

    Vinegar is an acid and can kill or reduce certain types of bacteria and viruses, such as E. coli and Salmonella, but not all pathogens.

    What germs does Meyers kill?

    Meyers is eco friendly and is good for cleaning dirt, grime and grease. 

    What is Agar?

    Agar is a jelly-like substance obtained from red algae that contains nutrients that supports the growth of bacteria.

LINKS

https://www.mayoclinic.org

https://www.who.int/news-room

https://www3.epa.gov

www.sciencedirect.com

https://www.mrsmeyers.com

Variables

Independent variable: type of cleaning solution. 

Dependent variable: amount of germs each cleaning solution kills.

Controlled variables:

  • Amount of cleaning solution applied 
  • Place we store the germs
  • How we swab the germs
  • Place where we are swabbing

Procedure

  1. Make Agar Solution:

Boil water in a sanitized pot, then let it cool to room temperature.  Pour the agar powder into the water and bring it to a boil while stirring frequently. Once the agar has cooled, pour it into 18 petri dishes and wait an hour for it to solidify.

  1. Prepare Testing Sites and Petri Dishes:

Tape off three square sections of the kitchen sink, fridge handle and kitchen counter. Label the petri dishes. Put on gloves and a mask to make sure germs don’t contaminate the testing area. Wet each taped off section with a cotton ball soaked in sterilized water, being careful to not touch the tape with the cotton ball.

  1. Swab Before Cleaning:

Swab the taped off sections with a sterilized cotton swab. A new swab is used for each section.  Then move the swabs in a zigzag pattern while rotating the swabs on the petri dishes filled with agar.   These are the control dishes.

  1. Swabbing After Cleaning:

Wipe down the three sections in each location with cotton balls drenched in Meyers for one section (in each location), Lysol for the second section (in each location) and vinegar water for the third section (in each location). A new cotton ball is used for each section.  Wait ten minutes and swab each section.  Move the swabs in a zigzag pattern while rotating them on the 9 remaining petri dishes filled with agar. Different petri dishes are used for each swab. 

  1. Observation Period:

Place the petri dishes in a dark, room temperature location and wait for the bacteria to appear. Compare the difference in the bacteria growth of the petri dishes before and after using the three different cleaning solutions.

 

 

 

Observations

Day 1: Nothing has appeared on the petri dishes, they all look the same.

 

Day 2: Bigger white dots, signs of bacteria, are starting to appear on the surfaces of the control petri dishes. One counter control petri dish has a full zigzag tray of medium yellow dots/bacteria.

 

Day 3: White dots are appearing on the petri dishes swabbed after cleaning solutions were applied.  The control petri dishes have dots that are turning yellow, the sink control petri dishes have many small dots and the counter control petri dishes have stayed the same.

 

Day 4: Nothing has really changed. The counter and handle control petri dishes have big yellow and white dots while the sink control petri dishes have a few big dots and a bunch of little ones. The cleaned sink petri dishes have a few big dots but no little ones.

Day 5: Little dots are starting to appear on all three handle petri dishes and one counter petri dish after the cleaning solutions were applied. Additional bigger dots are starting to appear on the sink petri dishes. The vinegar water is doing really well, they are almost completely clean, especially the counter. Meyers did well on the handle and got rid of the smaller dots on the sink. Lysol did well on the sink getting rid of the little dots like Meyers, but only did ok on the handle and counter.

 

Day 6: The control petri dishes big dots are getting bigger and also a bit more yellow. The sink still has a lot of little dots while the others don’t. And the petri dishes where the cleaning solutions were applied are the same, other than Lysol which is doing better on the handle and counter. The sink’s have more smaller dots than bigger dots.

 Day 7: The handle petri dishes after cleaning solutions were applied have a few more dots but everything is mostly the same as day 5. Lysol has cleaned most of the germs of the petri dishes the same as vinegar water, except the handle is still a bit dirty. Meyers didn't do as well but was still mildly effective. From what we see, Lysol has cleaned slightly more germs than vinegar water and more than Meyers.

 

 

Analysis

ANALYSIS

Based on our experiment we found that Lysol worked the best in killing the most germs.  Vinegar water was the second most effective, killing a significant number of germs. Meyers was the least effective in killing germs.  

We did this experiment twice.  The first time we swabbed right after applying the cleaning solution and found that the cleaning solutions did not kill many of the germs.  The second time we did the experiment we waited 10 minutes after applying the cleaning solutions and there was a significant increase in the number of germs that were killed. 

Conclusion

In conclusion, Lysol appeared to kill the most amount of germs, therefore the most effective. Although, the Vinegar Water was very close in results also killing many germs. Meyers was the least effective.  It took about three days for the first germs to appear and about 7 days for the results to be clear. 

 

Application

Helps to understand what cleaning products to use in day to day life to ensure that the most amount of germs are killed.  This will ensure that your home is clean and safe.

Sources Of Error

Sources of Error

- The sections taped off could have different amounts of germs.

- Swabbing technique could vary from location to location

- Petri dishes could have exposure to germs when opened to swab .

- The amount of cleaning solution applied could vary.

 

Acknowledgement

We would like to thank our parents for helping and providing guidance.  We would also like to thank our teacher, Mrs. Price, for supporting the science fair process.