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#1 teal



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Posted 26 March 2008 - 10:27 PM

For last semester bio lab we did an experiment where we took a liquid culture of non-pathogenic E. coli and spread it around on agar. Then we took sterile paper disks and dipped them in various solutions and placed them on the agar and let it incubate. The purpose was to see the effectiveness of various antimicrobials. We even tried different spices (the lab was really about the effectiveness of spices, but they tried various commercial products too). Well anyways, here's the result of the lab.

The first number is the size of the zone of inhibition, which is the circle around the disk where bacteria was not found growing. The next number is the number of bacterial colonies (bacteria grows is clumps) that are found within the zone of inhibition. So a big zone of inhibition and little or no colonies is good. No zone of inhibition (even with 0 colonies found in it) means the substance did not work at all (marked with just 1 zero). These are the averages from the 6 trials (per each category).

Neomycin 3.83, 0
Penicillin 1.83, 0
Streptomycin 5.33, 1
Ampicillin 8.17, 1.5
Control 0

Ammonia 0.67, 0
Lysol 4.25, 0
70% Ethanol 1.73, 21.5
10% Bleach 1.33, 0
Control 0

Hydrogen Peroxide 12.00, 1 (I assume it was %3 and only one plate showed 1 colony)
Listerine 4.00, 0 (one plate showed 299, but only 1, so it was excluded)
Antibacterial Soap 26.83, 0
Regular Soap 0
Control 0

Spices (just for fun, note that 1 zero means no zone of inhibition)
Garlic 6.60, 50
lemon 4.00, 0
mustard 0
oregano 0
ginger 0
onion 0
chili 0
lime 4.00, 0
allspice 0
control 0
pepper 0
control 0

Winner: Antibacterial soap, followed by hydrogen peroxide.
Loser: Ethanol and spices.

Now the main reason I've looked back at this old bio lab is that I have two LCs, one of which is already cloudy and another that is clear but is starting to get that disagreeable smell that the other one has. I've added a cap full of peroxide to one and doubled the volume of the other one with peroxide and was wondering if this would inhibit bacteria growth? I was thinking that I could transfer a small amount of it to another clean jar saturated with peroxide in it and get a clean culture.

#2 Hippie3



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Posted 26 March 2008 - 10:38 PM

very doubtful.
were yeasts tested as well ?

#3 teal



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Posted 26 March 2008 - 11:09 PM

No yeasts, only E. coli.

#4 teal



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Posted 27 March 2008 - 05:04 PM

Today the LC looked like this. I'm not sure whether this is healthy mycelium, metabolized honey or something else. It doesn't quite look like the large chunks I see in other pics. Also, the smell is still present. It was inoculated with spores a bit less than a week ago.

Posted Image

#5 Om shanti

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Posted 27 March 2008 - 05:27 PM

Is there any air exchange at all?
I am probably not the fastest animal in the forest around here. :horse: ...I have managed to have a few jars of LC go alcoholic, because of too little fresh air. It smells foul, actually worse than some bacterial infestations. Just an idea from the slow animal :)

Good luck.

#6 laughingsamsdice


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Posted 27 March 2008 - 05:34 PM

Tea tree oil i think is an interresting product...

#7 aumbrellaforainydays


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Posted 31 March 2008 - 03:27 PM

that antibacterial soap, was it salicylic acid or trilosan as the primary ingredient?

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