{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

calculating_cfu

calculating_cfu - MIC102L Spring 2009 CALCULATING CFU MIC...

This preview shows pages 1–2. Sign up to view the full content.

MIC102L Spring 2009 CALCULATING CFU MIC 102L Fall 2009 There are a number of different strategies for determining the CFU (colony forming units) in a liquid or solid sample. Some students might find the following explanation and definitions helpful. Adapted from http://www.science-projects.com/serdil.htm Hypothetical Example: In the following, a bottle contains an unknown concentration of bacteria ("CFU/ml" means "colony forming units per milliliter", where each CFU equals one LIVE bacterium). One milliliter from the bottle is transferred into a tube containing 9 ml of water or saline (0.15% NaCl is called "normal saline" or "NS"). Thus the concentration of the bacteria in the tube is exactly 1/10 that in the bottle. And if 1 ml of that is transferred into a second tube of 9 ml NS, another 10-fold dilution is accomplished. It is now 1/100 or 10 -2 the concentration in the bottle. The next dilution is made by removing 1 ml from the second tube and transferring it to 9 ml NS in the third tube, etc.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}