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Dilution and Colony-Forming Units

Ten grams of hamburger were added to 90 mL of sterile buffer. This was mixed well in a blender. One-tenth of a mL of this slurry was added to 9.9 mL of sterile buffer. After thorough mixing, this suspension was further diluted by successive 1/100 and 1/10 dilutions. One-tenth of a mL of this final dilution was plated onto Plate Count Agar. After incubation, 52 colonies were present. How many colony-forming units were present in the TOTAL 10 gram sample of hamburger?

Solution Preview

Ten grams of hamburger were added to 90 mL of sterile buffer. After blending this with sterile buffer, you have concentration of X in the hamburger/sterile buffer. You are making dilutions to find a concentration, after which you will have colony forming units. Colony forming units are colonies of bacteria that form from the replication of a single bacteria. So if you can dilute your sample to a ...

Solution Summary

This solution helps find the number of colony-forming units given information about dilutions. A step by step explanation is given, in 285 words.

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