How many cells would be alive after 2 minutes of treatment?
1000 cells An antimicrobial chemical was added to a population of bacteria. The initial population was 107 living cells (10,000,000). After 2 minutes, only 106 cells still remained alive. After another 2 minutes (4 minutes of total treatment), about how many cells would still be alive? 105
When does most of the cell death occur during antimicrobial treatment?
Most of the cell death occurs early in the treatment. The following microbial death curves were collected from a variety of antimicrobial treatments used on different E. coli samples. Arrange the graphs below in order of the effectiveness of these treatments.
How many cells were added to a population of bacteria?
An antimicrobial chemical was added to a population of bacteria. The initial population was 10 7 living cells (10,000,000). After 2 minutes, only 10 6 cells still remained alive.
How do you determine cell numbers after incubation?
To calculate the number of viable cells in the original sample, the number of colonies present after the plates have been incubated is multiplied by the dilution factor. The number of cells in a sample is usually expressed as colony forming units (CFU) per unit of volume (in this case mL) or CFU/mL.
Which of the following best describes why microbial death curves are typically plotted logarithmically?
Which of the following best describes why microbial death curves are typically plotted logarithmically? Bacterial population sizes are typically expressed in logarithmic form.
Which chemical agent would be the most effective to guarantee the broadest disinfection?
In a clinical situation where it is essential to control microbial growth that includes both mycobacteria and endospores, which chemical agent would be the most effective to guarantee the broadest disinfection? Chlorine has the best overall action against both of these targets.
Which of the following methods is usually effective in killing spores?
A process called sterilization destroys spores and bacteria. It is done at high temperature and under high pressure. In health care settings, sterilization of instruments is usually done using a machine called an autoclave.
What is the pattern of microbial death?
The Microbial Death rate is usually found to be constant over a period of time. Suppose a disinfectant claims it kills 90% of microbes, that means that under ideal conditions it should kill 90% in the first minute of exposure. If there were a billion, 100 million would be left.
Which of the following is true of an antimicrobial substance with a microbial death rate of 90% after 1 minute?
Which of the following is true of an antimicrobial substance with a microbial death rate of 90% after 1 minute? After the first minute of application of the agent, 10% of the original microbes are still left on the surface.
Does sterilant destroy all living microorganisms?
Sterilization describes a process that destroys or eliminates all forms of microbial life and is carried out in health-care facilities by physical or chemical methods.
When microbial control methods are used microbes are destroyed at a constant rate quizlet?
When microbial control methods are used, the microbial population is destroyed at a constant rate. That is, for each unit of time the treatment is applied to the microbial population, 90% of the population will be destroyed. There is no instantaneous death to the entire microbial population.
Which of the following methods would best reduce the number of microbes without altering the taste and chemical composition of beer?
Which of the following methods would best reduce microbes without altering the taste and chemical composition of beer? Pasteurization retains the properties of the alcohol and the protein structure. Although it does not destroy all microbes, it is adequate to destroy most of the harmful microbes while retaining flavor.
Do spores divide in 2 every 10 minutes?
In optimum (ideal) conditions some food poisoning bacteria can split in two every ten minutes, although at temperatures of around 10°c it may take up to ten hours or they may stop multiplying.
Which is correct regarding the rate of microbial death?
Which is correct regarding the rate of microbial death? Cells in a culture die at a constant rate.
How spore protect bacterial cell from dying?
The outer proteinaceous coat surrounding the spore provides much of the chemical and enzymatic resistance. Beneath the coat resides a very thick layer of specialized peptidoglycan called the cortex.