It is better that you check 1:10, 1:100, 1:1000 and etc dilution then set up your experiment.

Do the experiment - do not bother with lower dilutions.  Total microscopic cell countsl counts at 1E10/g  - culture will be somewhat less.http://aem.asm.org/content/27/4/678.full.pdf

Hi, please look in attach file

Hi there,

If you don't have any idea of the cell density of the sample it's difficult to tell... To make counting confortable you need to have 100 cfu or less per plate. If you plate 100µL per plate it means that cell density has to be 1000 cfu/mL or less. Just have a go with 1/10 1/100 1/1000 and 1/10000 and see.

It depends on the types of bacteria (aerobic or anaerobic), you are concerned. Firstly, You can try from 101 to 108 serial dilution if have no idea, then you will get a concept.

This way you can standardize the dilution of your sample for your experiment.

Dear Dr. Bhakti

Thank you for your interesting,  I have two types of bacteria in my project work. So, serial dilution is bother work , then precise level is an issue. 

Thanks a lot

A serial dilution is a series of sequential dilutions (repeated dilution) used to reduce a dense culture of bacterial cells to a more usable concentration.  It's commonly performed to determine density of bacteria, better to say, it depends on,  when you can count those bacteria and can determine how many bacteria are in your original sample taking into consideration of the dilution factor. A small amount of bacterial sample (as existed in the medium like soil, water, wastewater, or other contaminated medium) is mixed with a diluent and then successive dilutions are made.

Another important factor is the incubation period which also determine the density of the bacteria. You have to standardize the dilution for arriving at the countable bacterial density (cfu or colony forming units) at specific  incubation temperature for a definite incubation period. 

The ambience you need to inoculate and culture the bacteria will depend on the type of the bacteria - the aerobic or the  anaerobic class as well their nutritional/feeding demand. 

Hi Waleed,

To get in to your question, I am not sure what does it mean by "digestive chicken's micoflora"? Is it the sample of checken meat digested with external enzymes? If is so, you can get the bacterial load count by serial dilution (from10^5 to 10^8,  and aerobic agar plating. If it's a canned product, you have to try anaerobic plating also.  But if your sample is different from above, that's, if the sample is from digestive tracts of chicks, or in other words, if you are interested in the microflora of chicks' digestive tract, then you can't get your answer by simple serial dilution or agar plating. Because, microbial types & populations vary along within the digestive tract: hind gut>small intestine>stomach, and no single medium can support all species to grow well, and some species are unculturable with conventional culture media. So you need different approaches as total DNA sequencing, etc. Good luck.

Dear Dr. Mazumder

Thank you for your interesting answer, I mean that the microflora in the sample  of digesta not in the meat or anything eles.

Best regards

It is usually hit and trial before final decision is made, if you are unsure about microbial load in sample. Since it is digestive tract it is presumed to be highly loaded. So I would prefer atleast 100,000 dilution.

take the dilution from 10-5 to 10-8, normally micro-organisms are in abundance , if you go for 10-2 to 10-4 then it difficult to calculate TNTC i.e. Too numerous to count

Dear Dr Pandey

Thank you for your interesting and information , I'm  deeply appreciate to you. This answer that I looking for.

best wishes

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