A Roswell dairy wants to test it's milk for presence of Gram negative bacteria. A microbiology lab technician, sets up a serial dilution of a milk sample/bacterial culture as follows:
Tube 1: 5 ml of sample/bacterial culture is added to 15 ml diluent; Tube 2: 1 ml from Tube 1 is added to 99 ml diluent; Tube 3: 1 ml from Tube 2 is added to 99 ml diluent; Tube 4: 1 ml from Tube 3 is added to 9ml diluent. 100 ul of Tube 4 is plated onto a sterile MacConkey Medium plate.
After plating the final dilution on a MacConkey medium plate, she incubates the plate @
37 degrees C overnight. The next day she counts the number of bacterial colonies. She determines the number of colonies is 175.
Does the volume plated matter in determinizing the CFUs/ml? If yes, what is the dilution factor when 100 ul of tube 4 is plated?
A Roswell dairy wants to test it's milk for presence of Gram negative bacteria. A microbiology lab technician, sets up a serial dilution of a milk sample/bacterial culture as follows:
Tube 1: 5 ml of sample/bacterial culture is added to 15 ml diluent; Tube 2: 1 ml from Tube 1 is added to 99 ml diluent; Tube 3: 1 ml from Tube 2 is added to 99 ml diluent; Tube 4: 1 ml from Tube 3 is added to 9ml diluent. 100 ul of Tube 4 is plated onto a sterile MacConkey Medium plate.
After plating the final dilution on a MacConkey medium plate, she incubates the plate @
37 degrees C overnight. The next day she counts the number of bacterial colonies. She determines the number of colonies is 175.
Does the volume plated matter in determinizing the CFUs/ml? If yes, what is the dilution factor when 100 ul of tube 4 is plated?
Yes, the dilution factor is 1/2.
Yes. The dilution factor is 5X.
Yes, the dilution factor is 1000X.
No, The volume plated does not affect the number of bacterial colonies counted on the plate.
Yes. The dilution factor is 10X.
Yes. The dilution factor is 100X.