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Temperature for Incubation of Petri Dishes: LB Agar Plates

Postby technokinesis » Wed Jan 27, 2021 9:14 pm

:?: Question :?:


Here are the steps I did for my science experiment,
    I coughed on Luria Broth agar plates with three different face coverings (surgical, cloth, neck gaiter) and no mask.
    I then sealed the plates with masking tape and labeled them.
    I put these plates into a plastic container next to a portable heater and a lamp.
I measured the temperature the next day and it was 104 degrees Fahrenheit. I immediately turned off the lamp and adjusted the temperature and positioning of the portable heater and then the temperature went to 93 or so degrees Fahrenheit.

The DIY incubator and plates were at the temperature of 104 degrees for about 14-16 hours. It's been two days since I started this project and I haven't seen any bacterial colonies on my control group (the no mask trial). I'm unsure if the high temperatures killed the bacteria from my cough. Should I unseal the Petri dishes, cough on them again (redoing the procedure), and reincubate?

If it helps, these are the Petri dishes I ordered:

Picture of my incubation set up before I removed the lamp, the lamp is now removed to reduce the temperature:

Please respond to this and help me as soon as possible, as my project is due in 5-7 days.

Also, do you have any name ideas for this project? I was thinking, "Stop the Spread!" or "Viruses". Any suggestions are accepted! :D

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Re: Temperature for Incubation of Petri Dishes: LB Agar Plates

Postby probiotics » Wed Jan 27, 2021 10:16 pm


That's a timely project! While 37 degrees C is the average optimal temperature for bacteria to grow, I don't believe 40 C is high enough to kill your bacteria. Additionally, 2 days is probably too short of a time for you to begin to see bacterial growth. However, these are hypotheticals since the bacteria coughed onto the plate is unknown and is probably a mix of many different bacteria. I'd recommend giving it a few more days, or, if you have extra Petri dishes, repeat the experiment separately to ensure you get results. Good luck!

- probiotics

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