When Food Is Salted Water Diffuses Microorganisms Causing Them To And Die?

salt enters microorganisms causing them

to dry out and shrivel

.

What kills vegetative bacterial cells?

Boiling

: Heat to 100oC or more at sea level. Kills vegetative forms of bacterial pathogens, almost all viruses, and fungi and their spores within 10 minutes or less. Endospores and some viruses are not destroyed this quickly. However brief boiling will kill most pathogens.

Which of the following reduces the bacterial population of a liquid such as milk and destroys organisms that may cause spoilage and human disease?

Pasteurization

: Process developed by Louis Pasteur of heating milk, wine, or other liquids to 65–77°C (or the equivalent) for approximately 30 minutes to kill or markedly reduce the number of pathogenic and spoilage organisms other than bacterial spores.

Is the minimum amount of time required to kill microorganisms at a given temperature?

The lowest temperature at which all microorganisms are killed in 10 minutes is the thermal death point, while the minimum amount of time required to kill microorganisms at a given temperature is known as

the thermal death time

.

Why is moist heat more effective than dry heat for killing microbes?

Moist heat is generally more effective than dry heat for killing microorganisms

because of its ability to penetrate microbial cells

. Moist heat kills microorganisms by denaturing their proteins (causes proteins and enzymes to lose their three-dimensional functional shape).

How can microorganisms be destroyed?

1.

Heat (Temperature) Sterilization

: Fire and boiling water have been used for sterilization and disaffection since the time of the Greeks, and heating is still one of the most popular ways to kill microorganisms. … High heat combined with high moisture is one of the most effective methods of killing microorganisms.

How do you eliminate microorganisms?

Sterilization

is the process of destroying all living organisms and viruses. A sterile object is one free of all life forms, including bacterial endospores, as well as viruses. Disinfection is the elimination of microorganisms, but not necessarily endospores, from inanimate objects or surfaces.

Which method of microbial control destroys microorganisms?

Aseptic technique in the laboratory typically involves some dry-heat sterilization protocols using direct application of high heat, such as sterilizing inoculating loops.

Incineration

at very high temperatures destroys all microorganisms.

Which of the following is an agent that kills microorganisms or suppresses their growth?

Antimicrobial

—an agent that kills microorganisms or suppresses their multiplication or growth.

How are microorganisms destroyed by moist heat?

Moist heat destroys microorganisms by

the irreversible coagulation and denaturation of enzymes and structural proteins

. In support of this fact, it has been found that the presence of moisture significantly affects the coagulation temperature of proteins and the temperature at which microorganisms are destroyed.

What is thermal death time quizlet?

thermal death time.

The minimal time necessary to kill all microorganisms present in a culture held at a given temperature

.

Which bacteria has highest thermal death point?

Whereas Escherichia coli populations will be readily killed within 10 minutes at 212°F (100°C), spores of bacteria such as

Bacillus subtilus and Clostridium perfringens

will have a higher thermal death point, because a higher temperature is required to kill spores within 10 minutes.

What is thermal death time in microbiology?

Thermal death time is

how long it takes to kill a specific bacterium at a specific temperature

.

Why do microorganisms differ in their response to disinfectants?

Microorganisms differ in their response to disinfectants because

they have: Unique DNA characteristics of the microorganism

: In some bacteria, the…

Why are some microorganisms more resistant to heat?

Large populations or biofilms can increase heat resistance, possibly due to

the excretion of protective compounds

. Microorganisms are more heat sensitive during the log phase then during the stationary phase of the life cycle.

Which heat method dry or moist is more effective?

Moist and dry heat are the most common superficial heat therapy treatments. However,

moist heat is more effective than dry heat

in providing deeper penetration of the tissue at the same temperatures.

What is destroys microorganisms that are present in the object?

Sterilization

is the complete killing of all microorganisms in a material or on an object.

What is the destruction of all microbial life?

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.

Which one is the most effective method of killing microorganisms?

Explanation:

High temperatures combined with high moisture

are one of the most effective methods of killing microorganisms.

What can be used to destroy bacteria in food?

Extremely hot water of 140 degrees Fahrenheit or more is required to kill bacteria. Most restaurants rely on this method to kill bacteria on dishes and cooking utensils, and clean surfaces as well.

Chlorine

is also used to kill bacteria.

What defines a virus?

A virus is

a small collection of genetic code, either DNA or RNA, surrounded by a protein coat

. A virus cannot replicate alone. Viruses must infect cells and use components of the host cell to make copies of themselves. Often, they kill the host cell in the process, and cause damage to the host organism.

What microorganisms are most susceptible to disinfectants?

In general,

Gram-positive bacteria

are more susceptible to chemical disinfectants while mycobacteria or bacterial endospores are more resistant.

Which of the following types of radiation can damage microbes?

There are 2 general types of radiation used for sterilization,

ionizing radiation

and non-ionizing radiation. Ionizing radiation is the use of short wavelength, high-intensity radiation to destroy microorganisms. This radiation can come in the form of gamma or X-rays that react with DNA resulting in a damaged cell.

What is microorganism control?

Control of microorganisms is essential in order to prevent the transmission of diseases and infection, stop decomposition and spoilage, and prevent unwanted microbial contamination. Microorganisms are controlled by means of

physical agents and chemical agents

.

What is the process of destroying some but not all microorganisms?

The destruction or prevention of growth of most pathogens on living tissue is called antisepsis. Note that like

disinfection

, most, but not all, microorganisms are killed, and unlike both sterilization and disinfection, antisepsis refers to living tissue.

Which of the following microorganisms cause disease?

Do microorganisms placed in high concentrations of salts and sugars undergo lysis?

Microorganisms placed in high concentrations of salts and sugars undergo lysis. Ultraviolet light (UV) causes irreversible breaks in DNA strands. Some antimicrobial chemicals are considered to be disinfectants and antiseptics.

What is the complete destruction of pathogens and spores?

Sterilization

is the complete destruction of all forms of microbial life, including spores. Mechanical, chemical and biological indicators monitor the efficacy of these processes.

How does moist heat and dry heat sterilization eliminate microbial growth?

Moist Heat Sterilization

Moist heat causes

destruction of micro- organisms by denaturation of macromolecules

, primarily proteins. Autoclaving (pressure cooking) is a very common method for moist sterilization. It is effective in killing fungi, bacteria, spores, and viruses but does not necessarily eliminate prions.

Which of the following microorganisms cause disease that are a leading cause of death in developing countries because of lack of proper sanitation?

Cholera

is most likely to occur and spread in places with inadequate water treatment, poor sanitation, and inadequate hygiene.

Are microorganisms harmful or helpful?

Microscopic creatures—including bacteria, fungi and viruses—can make you ill. But what you may not realize is that trillions of microbes are living in and on your body right now.

Most don’t harm you at all

. In fact, they help you digest food, protect against infection and even maintain your reproductive health.

What is the thermal death curve?

Thermal death time is

a concept used to determine how long it takes to kill a specific bacteria at a specific temperature

. … Figure: Killing curve of C. botulinum: This curve presents the DR value (12.6 seconds) and the 12-D reduction (151 seconds) for C.

How is thermal death point determined?

Based on the growth of the bacteria

the thermal death point can be estimated. The quadrant in which there is no growth is the temperature and the time required to destroy the bacteria.

How will you determine the thermal death point and thermal death time?

One way to do this is to determine the thermal death point (TDP) and the TDT (thermal death time). The TDT is

the minimum time it takes to kill a population of microbes at a specific temperature

. The TDP is the lowest temperature that is required to kill a population of microbes when applied for a specific time.

What is the thermal death time for the culture?

A bacteria culture is heated in 100°C water; based on the picture below, what is the thermal death time for that temperature? The thermal death time for that temperature is

40 minutes

because that is when all bacteria have been killed and are no longer present.

What two variables contribute to the thermal death time?

The time required to kill a known population of microorganisms in a specific suspension at a particular temperature is referred to as thermal death time (TDT).

Increasing the temperature decreases TDT, and lowering the temperature increases TDT

.

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

. Most of the cell death occurs early in the treatment. Different treatments vary in the length of time required to kill all microbes.

What is E coli thermal death point?

With the moist heat, bacteria E. coli is killed at

80° C at 10 minutes

which is known as the thermal depth point and the thermal death time is the same with the temperature.

What is the thermal death point of Staphylococcus aureus?

All isolates of S. aureus died when the temperatures were increased to

70 oC and 80 oC

, at 50 and 20 minutes, respectively.

How does pH affect thermal death time?

These results affirm that the bacteria subjected to thermal stress at 35°C under slightly acidic environment (pH 6.0) required the highest

increase in temperature

to obtain the thermal death decimal reduction time.

Does all the disinfectants will have similar effect on different microorganisms?

Generally not recognized, however, is that

all disinfectants are not similarly affected by concentration adjustments

. … Several physical and chemical factors also influence disinfectant procedures: temperature, pH, relative humidity, and water hardness.

What do we mean when we say that a disinfectant is bactericidal?

The main defining feature of a bactericidal substance is that

these antimicrobial treatments directly kill bacteria

. These agents “attack” microbes by affecting the cell wall, lipids, enzymes, or protein synthesis within the cell – sometimes even completing a combination of these mechanisms.

What do we mean when we say that microbes are ubiquitous?

Microorganisms are ubiquitous; that

is, they are present nearly everywhere

. In this lab you will try to isolate bacteria and other microorganisms from various sources using different types of media.