A researcher analyzes unpasteurized apple juice suspecting E. coli contamination of the juice. He/she plates out 0.1 mL of a 10-2 dilution of juice on each plate and grows up the plates. He/she then counts colonies on each plate. Plate 1 – 242 colonies Plate 2 – 237 colonies Plate 3 – 249 colonies a. Calculate the CFU/mL for this juice. Show formula used and include units. b. If acceptable levels of E. coli in juice were 0.02 CFU/ml juice, would this juice be acceptable for human consumption? Why or why not?

A researcher analyzes unpasteurized apple juice suspecting E. coli contamination of the juice. He/she plates out 0.1 mL of a 10-2 dilution of juice on each plate and grows up the plates. He/she then counts colonies on each plate. Plate 1 – 242 colonies Plate 2 – 237 colonies Plate 3 – 249 colonies a. Calculate the CFU/mL for this juice. Show formula used and include units. b. If acceptable levels of E. coli in juice were 0.02 CFU/ml juice, would this juice be acceptable for human consumption? Why or why not?

Basic Clinical Laboratory Techniques 6E

6th Edition

ISBN:9781133893943

Author:ESTRIDGE

Publisher:ESTRIDGE

Chapter6: Basic Clinical Chemistry

Section6.8: Fecal Occult Blood Test

Problem 1CS

See similar textbooks

Similar questions

A researcher analyzes unpasteurized apple juice suspecting E. coli contamination of the juice. He/she plates out 0.1 mL of a 10-2 dilution of juice on each plate and grows up the plates. He/she then counts colonies on each plate. Plate 1 – 242 colonies Plate 2 – 237 colonies Plate 3 – 249 colonies Calculate the CFU/mL for this juice. Show formula used and include units
A laboratory technician performed a series of 10 fold serial dilutions shown below. he plated 0.1 mL from each dilution tube onto NA and got the follow numbers per plate dilution 1:10 1:10 1:100 1:1000 1:10000 1:100000 colony count >1000 >1000 808 303 38 3 calculate the concentration of bacteria in the undiluted stock (in CFU/mL)
Below is a diagram of the serial dilution of a culture with 1 x 10º cells. Fill out the missing information. 250 Culture Diluent 1 x 10° cells/mL 9 mL 9 mL 9.9 mL 9.9 mL 99.9 mL Volume to add to diluent Final Dilution level Theoretical count after plating 100 uL
1 ml of a patient sample was added to 999 ml of media. From this 0.1 ml was transferred to the plate. After 24 hours there were 60 colonies on the plate. What is the dilution factor here. What's the number of bacteria per ml of the original patient sample. a. The dilution factor is 1000. The patient sample contains 600 cells/ml b. The dilution factor is 1000. The patient sample contains 600,000 cells/ml c. The dilution factor is 100. The patient sample contains 600,000 cells/ml d. The dilution factor is 10. The patient sample contains 6000 cells/ml e. It cant be determined its too many cells
Refer to the following diagram: 100 ul 100 uL 100 pl 100 µL 100 pl 100 pL 100 pl Volume to transfer A B C D E F G 900 uL in each tube 10 102 10 10 10 10 10 Dilutions E.CoN culture Volume of the diluted sample plated 100 ul 100 μL 100 pL 100 ul Volume of the 10 ml 10 ml original sample plated 10 ml 10 ml Plate D Plate E Plate F Plate G Given that Plate D has too many colonies to count, and Plate G has no colonies at all as a result of serial dilution, draw out all four plates and demonstrate what they might look like (assuming serial dilution has been performed correctly). Based on your drawings, identify the number of CFU/ml for Plate E and Plate F. Show your calculations.
This agar plate was obtained by spreading 0.1 ml of a 1:1,000 dilution of a bacterial sample taken from cole slaw, and then incubating at 37oC for 24h. This plate indicates that: a. there are 42 bacteria/ml on the cole slaw b. there are at least 4 different types of bacteria in the cole slaw c. there are approximately 42,000 bacteria/ml in the cole slaw sample d. there are approximately 420,000 bacteria/ml in the cole slaw e. these bacteria cannot cause illness because they came from the person’s skin who made the cole slaw
You are given a bacterial culture which has a concentration of approximately 5.0 x 10^8 cells/mL. List a series of dilutions and platings that you could carry out in order to determine the exact concentration of the culture. Note that you must plate four plates from a minimum of two dilution tubes. The volumes plated should be in the range of 0.1 mL – 1.0 mL. Duplicate volumes may not be plated from any one dilution tube. Each plating should aim for a count between 30 and 300 CFUs. You can select any value from 30-300 for CFU and any volume from 0.1-1.0 to find out dilution scheme
A sterile powder vial label indicates to add 3.4 mL of sterile water which will produce a final volume of 4 mL. The increased volume is the result of: Select one: O a. O b. C. O d. The powder inside the vial was not lyophilized The type of diluent Displacement of the powder Incorrect calculation /mod/quiz/attempt.php?attempt=186101&cmid=102359&page=49# Q Search D L 贊助 8 9 Time left 22:22:18 HO
The number of bacterial cells in a culture broth is to be determined by a culture technique. Serial dilutions were performed and a 0.1 mL aliquot from each dilution was spread onto Plate Count Agar (PCA). The number of bacterial colony forming units (CFU) after overnight incubation are shown as listed in the table below. What is the number of colony forming units per mL of the culture broth? Choose only the most appropriate plate for your calculation. Give your answer as the number only (do not add text for the units). You may use scientific notation with the format 1.12e+6 (that is, 1.12 x 106 cfu/mL). (Note: Canvas will then display your answer a whole number.) Plate 1 10 Plate 2 10 Plate 3 10 dilution dilution dilution Plate 4 10 dilution Plate 5 107 dilution Plate 6 10 dilution -6 *Too many to count Number of colony forming units (CFU) TMTC* TMTC* 840 28 19 1
You are testing unpasteurized milk for the presence of bacterial contamination. Starting from the undiluted milk, you do serial dilutions, and plate 0.5 ml of 4th dilution on agar. If you counted 78 CFUs from the 4th plate, how many bacteria/ml do you expect? (show solution) Do you think standard plate counts are very accurate? Why or why not?
The number of bacterial cells in a culture broth is to be determined by a culture technique. Serial dilutions were performed and a 0.1 mL aliquot from each dilution was spread onto Plate Count Agar (PCA). The number of bacterial colony forming units (CFU) after overnight incubation are shown as listed in the table below. What is the number of colony forming units per mL of the culture broth? Choose only the most appropriate plate for your calculation. Give your answer as the number only (do not add text for the units). You may use scientific notation with the format 1.12e+6 (that is, 1.12 x 106 cfu/mL). (Note: Canvas will then display your answer a whole number.) Plate Dilution Plate 1 10 dilution Plate 2 10 dilution Plate 3 107 dilution Plate 4 10 dilution Plate 5 107 dilution Plate 6 100 dilution *Too many to count Number of colony forming units (CFU) TMTC* 382 83 10 2 0
You are working in a medical lab and receive a urine sample from a patient that is displaying urinary tract infection symptoms. You use the urine to set up 8 serial 10-fold dilutions. You decide to spread plate 100 µl of different dilutions. The colony count after incubation overnight: 10-4 dilution has 173 colonies. What is the cfu/ml of this culture?