You are interested in the microbial count in some milk you bought from the grocery store, but then realized it was sour. You measure 1 mL and add it to 9 mL of saline, making 10 mL of diluted milk. One mL of this dilution is then added to 9 mL of saline. This is repeated two more times. Finally, 1 mL of this last dilution is placed in a Petri plate and nutrient agar is poured into a Petri dish. You count 287 colonies. Determine the total cell count in CFU/mL of the original milk.
Added by Harold G.
Step 1
- 1st dilution: 1 mL in 10 mL = 1:10 dilution - 2nd dilution: 1:10 dilution x 1:10 dilution = 1:100 dilution - 3rd dilution: 1:100 dilution x 1:10 dilution = 1:1000 dilution - 4th dilution: 1:1000 dilution x 1:10 dilution = 1:10000 dilution Show more…
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