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? This problem has been solved! An antimicrobial chemical was added to a population of bacteria. The initial population was 107 living cells (10,000,000).
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 used to preserve food by slowing?
Refrigeration preserves food by slowing down the growth and reproduction of microorganisms and the action of enzymes which cause food to rot.
How do you calculate microbial growth?
The rate of exponential growth of a bacterial culture is expressed as generation time, also the doubling time of the bacterial population. Generation time (G) is defined as the time (t) per generation (n = number of generations). Hence, G=t/n is the equation from which calculations of generation time (below) derive. 3.
What are the 4 phases of bacterial growth?
For this reason, graphs that show the growth of bacterial cultures are plotted as the logarithm of the number of cells. Bacterial colonies progress through four phases of growth: the lag phase, the log phase, the stationary phase, and the death phase.
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.
What is the process of treating and handling food to stop and slow down the spoilage?
Food preservation can be defined as the process of treating and handling food in such a way as to stop or greatly slow down spoilage and prevent foodborne illness while maintaining nutritional value, texture and flavour.
Is a method that involves the process of treating and handling food to stop or slow down the spoilage and to allow for longer storage?
Preservation: Food preservation is the process of treating and handling food to stop or slow down food spoilage, loss of quality, edibility, or nutritional value and thus allow for longer food storage.
What is preservation in biology?
Preservation and conservation are both processes that protect the environment, but their approaches are somewhat different. The goal of preservation is to protect the environment from the harmful effects of human activity. 5 - 8. Biology, Climatology, Earth Science, Ecology, Geography, Human Geography.
What is the process of filtration?
Filtration is the passage of a liquid or a gas through a screenlike material with pores small enough to retain microorganisms. A vacuum is typically used to force the liquid through the mesh, and then the sterile liquid or gas is collected in a sterile container on the other side. Nonionizing radiation, such as UV light, ...
How do disinfectants work?
Disinfection can occur by physical or chemical means. Disinfectants are used to inhibit or destroy pathogens. Assume that you have an antimicrobial agent specific for each of the targets listed below. Indicate which type of microbe would be most susceptible to the agent by placing it in the appropriate bin.
What is the process that removes water from microorganisms, leaving them unable to grow or reproduce,
Desiccation is a process that removes water from microorganisms, leaving them unable to grow or reproduce, but still viable. Osmotic pressure is a process that uses high concentrations of salts and sugars to preserve food.
How are bacteria's population sizes expressed?
Bacterial population sizes are typically expressed in logarithmic form. Most of the cell death occurs early in the treatment. Different treatments vary in the length of time required to kill all microbes. It takes longer to kill all members of a large population than a smaller one.
How do phenolics and alcohols affect the cell membrane?
Phenolics exert antimicrobial activity by injuring lipid-containing plasma membranes, which causes the cellular components to leak out of the cell. Alcohols exert their action by denaturing proteins and dissolving lipids. High pressure is used to denature proteins in vegetative cells.
What is the process of preserving food?
Osmotic pressure is a process that uses high concentrations of salts and sugars to preserve food. Filtration is the passage of a liquid or a gas through a screenlike material with pores small enough to retain microorganisms. A vacuum is typically used to force the liquid through the mesh, and then the sterile liquid or gas is collected in ...
Can invasive procedures provide a portal of entry for bacteria?
invasive procedures can provide a portal of entry for bacteria. None of the answers is correct; all of these factors may contribute to hospital-acquired infection. None of the answers is correct; all of these factors may contribute to hospital-acquired infection.