How to calculate CFU/ml in settle plate technique used in pharmaceutical industries?

Dear all, please help me to get correct idea about CFU/ml

In this technique u can count individual colonies and where as some colonies or clubbed and some or cover half of plate u should count as one colony or otherwise u can divide plate into four parts and see I colony counter if colony spread out of one part it can be count as one but be countious when spreading if u could not spread uniformly it get all clubbed colonies.

Dear Microbiologist… The term Cfu/ml is not use in settle plate technique bcoz we expose the plate for particular time(4hour) so how can we give the result in Cfu/ml. For settle plate tech. we should give the result Cfu/4 hour.

I agree cfu/ml is not used in settle plate which is generally used for environment monitoring cfu/plate is the limit. 4 hr is harmonised time for settle plate due to different reasons. Many limits are 100 cfu/ plate or 50 or 1 depending on the classification of the area


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