How well do disinfectants

[fisherm72]

we did the project how well do disinfectants work. we ordered the augars from science buddies. Once we cleaned the cutting board and rubbed it with a cotton swab, we then rubbed the cotton swap on the augar. but we didn't have any bacteria grow on the augar. any suggestions?

[MadelineB]

Hello and welcome to Science Buddies,

So here are some questions for you, based on the procedure section for this project:

https://www.sciencebuddies.org/science- ... #procedure

How long did you wait after wiping the board with lunch meat until you used the 5 different disinfectants?

Did you divide the cutting board into 6 sections and use 5 different disinfectants (+ water as a control)

How long did you let the agar plates sit?

Did you see any growth in the agar plate for the control (water)?

Maybe your answers to the above questions will help us figure out what might have happened! Thanks!

[fisherm72]

Thanks for your response. We waited about 18 hours before cleaning the cutting board. Yes, we divided it into sections and no, we didn't see any cultures for even the water cleaned section. I waited 4 days and saw no cultures grow on any augars.
After some research of my own, I read that maybe 18 hours was too long, possibly the bacteria died. So I tried the experiment again. This time we used raw chicken on the cutting board instead of meat. I also used a plastic serving dish instead of the cutting board (because I thought maybe the anti microbial cutting board killed the bacteria). I also performed the cleaning process immediately overnight (so just 12 hours instead of 18 hours. And still - no cultures at all?!
How exactly should I store augars to grow bacteria? any other suggestions?

[fisherm72]

I should add that we did use 5 disinfectants and a water control. I should add that I did have 2 culture dots grow on augar 6, which was Lysol Spray. But nothing on any of the other, not even the water control. Because nothing grew on #1 the water control or any others I feel like that 1 culture must of been some other contaminant, not from the bacterial we tried to grow. Also the 2 cultures that grew on #6 proove that the augars were 'good' and the storage was good. The problem must lie within our attempt to grow bacterial. Hoe else can we grow bacteria? We followed the science buddies instructions exactly.

[MadelineB]

Puzzling!
could you just clarify what you mean when you say "Once we cleaned the cutting board and rubbed it with a cotton swab, we then rubbed the cotton swap on the augar"? Did you clean the entire board with something? or did you only clean each section with the "assigned" disinfectant?

Did you use a separate swab/Q-tip for each culture?

And, how did you make sure that the Lysol spray didn't land on any of the other sections? I apologize for all the questions, but I'm trying to narrow down why you didn't get any growth, even for the section that should have only been cleaned with water.

Maybe you could get a "regular" cutting board if maybe the antibacterial board was eliminating the growth!

Also, where and how long are you storing the agar plates while they are incubating?

Thanks for your patience! Maybe we can solve this puzzle!