Which Toilet is The Cleanest?
By Ros Emeyra binti Zulkefli
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Even if it looks clean, toilet may still be home to hidden bacteria. Maintaining a truly hygienic toilet requires more than a quick scrub.
Even if it looks clean, toilet may still be home to hidden bacteria. Maintaining a truly hygienic toilet requires more than a quick scrub.
Why Toilet Cleanliness Matter
Health and hygiene
Health and hygiene
A dirty toilet can carry harmful bacteria like E.coli, Salmonella and Norovirus.
Odor control
Odor control
Proper cleaning prevents unpleasent smells.
Experiment to Find Out Which Toilet is The Cleanest
Swab Test and Agar Plate Experiment
Swab Test and Agar Plate Experiment
Objective
To identify which toilet is cleanest by detect the presence of bacteria and visually compare the cleanliness of different toilets.
Apparatus and Materials
Cotton swab, agar plate, labels, gloves, permanent marker and notebook.
Procedure:
Comparing Toilets Based on Position
Wear the disposable gloves and gather cotton swabs, agar plates, a permanent marker, and labels.
Label each agar plate with the toilet location with different position. For example, toilet 1 (closest to door), toilet 2 (middle position) and toilet 3 (farthest from door).
Go to the selected toilet and identify at least three position toilet from the door which is closest to the entrance door, in the middle and farthest to the entrance door.
For each cubicle, choose a standard surface to test, such as the toilet seat, flush handle, or door latch.
Take a cotton swab and gently rub it on the selected surface for 10–15 seconds, using a zigzag motion. Use a new swab for each surface to avoid cross-contamination.
Gently press and rub the swab onto the corresponding agar plate using the same zigzag pattern. Do not apply too much pressure or damage the agar surface.
7. Seal the plate and repeat the same process for the next cubicle, and then repeat for other position toilets.
8. Place the agar plates in a warm area or incubator at around 30–37°C for 2–3 days, away from direct sunlight.
9. After incubation, observe the growth of bacteria colonies without opening the plates. Record the number, color, and size of bacterial colonie.
10. Compare the results between the toilet cubicles that are closer to the entrance, in the middle and farther away to determine which one has more bacterial growth.
11. Analyze whether the position of the toilet has an impact on cleanliness, possibly due to frequency of use or airflow.
12. Dispose of the materials properly and safely. Seal used agar plates in biohazard bags and wash your hands thoroughly after the experiment.
Observation and Results
After the incubation period, observe the bacterial colonies on each agar plate without opening the lid to avoid contamination or exposure to harmful microbes.
Record the number of colonies, color of colonies (white, yellow, cream) , size and shape of colonies in notebook for each samples.
Compare the results between cubicles that are closer to the entrance, in middle position and farther inside.
Use the data to analyze whether toilet position affects cleanliness, taking into account factors like cleaning frequency, user behavior, and ventilation.
Let's See How It Works:
Let's See How It Works:
Experiment to Try at Home: Growing Bacteria
Toothbrush Bacteria Test
Toothbrush Bacteria Test
Objective
To compare bacteria on used vs. unused toothbrushes.
Apparatus and Materials
2 toothbrushes (one used, one new), slices of potato, cotton swabs and ziplock bags
Procedure:
Label potato slice as “Used Toothbrush” and the other as “New Toothbrush.”
Using a sterile cotton swab, gently rub the bristles of the used toothbrush.
Lightly press the swab in a zigzag motion on the surface of the potato slice labeled “Used Toothbrush.”
Repeat the process with the new toothbrush using a new cotton swab and press it onto the plate labeled “New Toothbrush.”
7. Seal both containers using lids or ziplock bags to prevent contamination.
8. Place the plates in a warm area away from direct sunlight, such as inside a closed box or cupboard.
9. Observe daily for 3 to 5 days. Do not open the containers once bacteria begin to grow.
10. Record any visible changes, such as the number, size, and color of bacterial colonies.
Observation and Expected Results:
The used toothbrush is expected to show more bacterial growth, as it has been exposed to the mouth, bathroom air, and possibly moisture buildup. The new toothbrush should show little or no growth if properly stored
Clean Potato
Clean Potato
Dirty Potato (Bacteria grow)
Dirty Potato (Bacteria grow)
Curious about how fast mold can grow on a dirty vs clean potato?
Watch this video:
We hope you enjoyed learning about bacteria growth through
simple home experiments. Keep exploring science in everyday life!
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