Aerobic Colony COunt Units

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kady123
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Aerobic Colony COunt Units

Post by kady123 » Thu Feb 05, 2009 8:54 pm

Greetings,
I did the following:
1. Blended 25 g of meat with 225 ml of diluent (1:10 dilution)
2. Performed serial dilutions for above(1:100, 1:1000 and 1:10000)
3. Inoculated 1 ml of the solution of PCA (Plate count agar)
3. Counted the aerobic colonies (ACC)

Is the result in CFU/ml or CFU/g? Are they both the same for this case? If it is not CFU/g, how can I get the answer in this unit??

Thank you in advance!

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canalon
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Post by canalon » Fri Feb 06, 2009 4:37 am

results can be given in cfu/g. Just calculate the dilution factors to account for the dilutions and the fact that you diluted only 1ml of 250ml
Patrick

Science has proof without any certainty. Creationists have certainty without
any proof. (Ashley Montague)

JorgeLobo
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Re: Aerobic Colony COunt Units

Post by JorgeLobo » Fri Feb 06, 2009 10:59 am

Presuming you're reporting the estimated count in the meat - it's cfu/g not cfu/ml. The amount of fluid diluting is not considered i n estimating counts - the dilution factor is the parameter of significance.

You should be using 0.1 ml. 1 ml is alot to go on a plate, will often give you smeared colonies and any spreaders are going to make it uncountable.

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canalon
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Post by canalon » Sat Feb 07, 2009 1:49 pm

Not if he is preparing pour plates. Otherwise agreed.
Patrick

Science has proof without any certainty. Creationists have certainty without
any proof. (Ashley Montague)

kady123
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Re: Aerobic Colony COunt Units

Post by kady123 » Sat Feb 07, 2009 2:41 pm

hello,
i am using the pour plate method!
thanks

JorgeLobo
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Post by JorgeLobo » Sat Feb 07, 2009 5:08 pm

Great and the dilutions are about right. Good luck.

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