Podcast
Questions and Answers
What effect does increasing the acid or alkalinity in a food have on the killing effect of heat?
What effect does increasing the acid or alkalinity in a food have on the killing effect of heat?
- Slows down the killing effect of heat
- Increases the heat resistance of bacteria
- Speeds up the killing effect of heat (correct)
- Has no impact on the killing effect of heat
Which pH range categorization is correct for sauerkraut and pickles according to the text?
Which pH range categorization is correct for sauerkraut and pickles according to the text?
- Medium acid to acid: pH 3.7 - 4.6
- Low acid: pH > 4.6
- Alkaline: pH > 7.0
- High acid: pH < 3.7 (correct)
What is the term used to describe the ability of bacteria to produce stress proteins enabling them to grow in acid environments?
What is the term used to describe the ability of bacteria to produce stress proteins enabling them to grow in acid environments?
- Acid adaptation
- Acid tolerance
- Acid habituation (correct)
- Acidification
What does the text suggest about E.coli O157:H7 in relation to acidity?
What does the text suggest about E.coli O157:H7 in relation to acidity?
In terms of heat resistance, when are most bacteria maximally resistant?
In terms of heat resistance, when are most bacteria maximally resistant?
What is the equilibrium favored when the exterior pH is 4.0 and the pKa is 4.0?
What is the equilibrium favored when the exterior pH is 4.0 and the pKa is 4.0?
Intracellular pH of 7.0 results in the equilibrium favoring the formation of which compound?
Intracellular pH of 7.0 results in the equilibrium favoring the formation of which compound?
What is the role of ATPase in the process described?
What is the role of ATPase in the process described?
A highly oxidized substrate, with a positive Eh value, is likely to support the growth of which type of microorganisms?
A highly oxidized substrate, with a positive Eh value, is likely to support the growth of which type of microorganisms?
What does the redox potential (ORP) value of a food indicate?
What does the redox potential (ORP) value of a food indicate?
Which term refers to organisms that grow at 5-7 degrees Celsius regardless of their optimum growth temperature?
Which term refers to organisms that grow at 5-7 degrees Celsius regardless of their optimum growth temperature?
What happens to proteins above the maximum temperature for an organism?
What happens to proteins above the maximum temperature for an organism?
Which two pathogens mentioned are both mesophiles and psychrotrophs?
Which two pathogens mentioned are both mesophiles and psychrotrophs?
What effect does temperature have on chemical and enzymatic reactions in living organisms?
What effect does temperature have on chemical and enzymatic reactions in living organisms?
What do yeast and mold have in common regarding their growth temperature ranges?
What do yeast and mold have in common regarding their growth temperature ranges?
How does temperature below the minimum affect the growth of organisms?
How does temperature below the minimum affect the growth of organisms?
Which of the following is an example of an exogenous osmolyte?
Which of the following is an example of an exogenous osmolyte?
What happens to the cell membrane composition when bacteria take up exogenous osmolytes?
What happens to the cell membrane composition when bacteria take up exogenous osmolytes?
What is the pH range for acidophiles?
What is the pH range for acidophiles?
In what pH range do nearly all yeasts and molds have their optimum pH?
In what pH range do nearly all yeasts and molds have their optimum pH?
What happens to bacterial growth as pH increases from the optimum to the maximum?
What happens to bacterial growth as pH increases from the optimum to the maximum?
What is the effect of an environment with a pH beyond the range for Vibrio cholerae?
What is the effect of an environment with a pH beyond the range for Vibrio cholerae?
What is one of the molecular adaptations of psychrophiles to lower temperatures?
What is one of the molecular adaptations of psychrophiles to lower temperatures?
What is the role of unsaturated fatty acids in the cytoplasmic membranes of psychrophiles?
What is the role of unsaturated fatty acids in the cytoplasmic membranes of psychrophiles?
What type of microorganisms survive pasteurization but do not grow at pasteurization temperature?
What type of microorganisms survive pasteurization but do not grow at pasteurization temperature?
Which type of bacteria includes Bacillus and Clostridium as examples?
Which type of bacteria includes Bacillus and Clostridium as examples?
What is a characteristic of the membrane fatty acids in psychrotropic bacteria?
What is a characteristic of the membrane fatty acids in psychrotropic bacteria?
What are heat shock proteins in thermophiles known for?
What are heat shock proteins in thermophiles known for?
