Microbiology: An Introduction (13th Edition)
13th Edition
ISBN: 9780134605180
Author: Gerard J. Tortora, Berdell R. Funke, Christine L. Case, Derek Weber, Warner Bair
Publisher: PEARSON
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Textbook Question
Chapter 6, Problem 3CAE
The number of bacteria in saliva samples was determined by collecting the saliva, making serial dilutions, and inoculating nutrient agar by the pour plate method. The plates were incubated aerobically for 48 hours at 37°C.
| Bacteria per ml Saliva | ||
| Before UsingMouthwash | After UsingMouthwash | |
| Mouthwash 1 | 13.1 × 106 | 10.9 × 106 |
| Mouthwash 2 | 11.7 × 106 | 14.2 × 105 |
| Mouthwash 3 | 9.3 × 105 | 7.7 × 105 |
What can you conclude from these data? Did all the bacteria present in each saliva sample grow?
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The number of bacteria in saliva samples was determined by collecting the saliva, making serial dilutions, and inoculating nutrient agar by the pour plate method. The plates were inoculated aerobically for 48 hours at 37°C.
What can you conclude from this data? Why?
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The students of a Microbiology class were tasked to transfer or subculture a pure culture of Escherichia coli bacterium in five 7 mL nutrient broth and five petri dishes of nutrient agar with 20 mL capacity each. Based on the instruction bottles for nutrient broth and nutrient agar, preparation of the culture media is as follows.
Nutrient broth: 8 g/liter
Nutrient agar: 28 g/liter
Answer the following:
a. What is the weight in grams of nutrient broth?
b. What is the weight in grams of nutrient agar?
c. What is the distilled water in mL for nutrient broth?
d. What is the distilled water in mL for nutrient agar?
Do you think standard plate counts are very accurate? Why or why not?
When doing serial dilutions, why is it necessary to plate more than one dilution?
You left a carton of orange juice on your counter for 3 days. When you taste it, it is very bubbly (as though it was carbonated), and it tastes more bitter than usual. (Note: acids taste bitter). What do you think could have happened? (Note: you can’t just say that bacteria grew—you must explain how the growth of the bacteria resulted in the changes in the orange juice.)
Based on what you now know about the presence of bacteria on chicken and beef, why is it a good idea to use separate chopping boards for meat and for vegetables?
Please help me thank you
Chapter 6 Solutions
Microbiology: An Introduction (13th Edition)
Ch. 6 - Prob. 1RCh. 6 - Prob. 2RCh. 6 - Prob. 3RCh. 6 - Seven methods of measuring microbial growth were...Ch. 6 - By deep-freezing, bacteria can be stored without...Ch. 6 - A pastry chef accidentally inoculated a cream pie...Ch. 6 - Nitrogen and phosphorus added to beaches following...Ch. 6 - Differentiate complex and chemically defined...Ch. 6 - DRAW IT Draw the following growth curves for E....Ch. 6 - NAME IT A prokaryotic cell hitched a ride to Earth...
Ch. 6 - Two culture media were inoculated with four...Ch. 6 - Two culture media were inoculated with four...Ch. 6 - Use the following graph to answer questions 3 and...Ch. 6 - Use the following graph to answer questions 3 and...Ch. 6 - Assume you inoculated 100 facultatively anaerobic...Ch. 6 - The term trace elements refers to a. the elements...Ch. 6 - Which one of the following temperatures would most...Ch. 6 - Which of the following is not a characteristic of...Ch. 6 - Which of the following types of media would not be...Ch. 6 - An organism that has peroxidase and superoxide...Ch. 6 - E. coli was incubated with aeration in a nutrient...Ch. 6 - Clostridium and Streptococcus are both...Ch. 6 - Most laboratory media contain a fermentable...Ch. 6 - Flask A contains yeast cells in glucose-minimal...Ch. 6 - Clinical Applications and Evaluation 1. Assume...Ch. 6 - Heat lamps are commonly used to maintain foods at...Ch. 6 - The number of bacteria in saliva samples was...
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