Control of Microbial Growth Part 1A

inanimate objects that may harbor and transfer disease-causing microbes (including bacteria and viruses):

fomites

instruments and equipment needed for invasive surgery need to be completely _____ (e.g., scalpels, gloves in operating rooms).

sterile

instruments and equipment for external applications are often ____ (e.g., stethoscopes, blood pressure cuffs) but not completely sterile.

disinfected

destruction of all vegetative cells, endospores, and viruses from the targeted item or environment:

sterilization

sterilization is achieved through physical or chemical procedures. true or false?

true

collection of techniques to prevent contamination of sterile surfaces (maintain asepsis):

aseptic technique

failure to practice aseptic technique during clinical procedures may introduce microbes to the patient’s body, putting them at risk for:

sepsis

medical procedures that carry risk of contamination are performed in a:

sterile field

____ of food uses heat at a temperature low enough to preserve food quality but high enough to destroy common food-borne pathogens, including those that form endospores like clostridium botulinum.

commercial sterilization

low and medium acid food are heated to ____°C for a minimum of 2.52 minutes.

121

acidic food do not need to be heated due to their acidicty. true or false?

true

process that inactivates most microbes on the surface of a fomite by using antimicrobial chemicals or heat:

disinfection

good ____ are fast acting, stable, easy to prepare, inexpensive, and easy to use.

disinfectants

antimicrobial chemicals safe for use on living skin or tissues:

antiseptics

process of applying an antisepsis:

antisepsis

able to penetrate the tissue without causing damage:

antiseptics

used on abiotic surfaces:

disinfectants

must be sterile because they are used inside the body:

critical items

surgical instruments, catheters, intravenous fluids are examples of:

critical items

requires a high level of disinfection (not sterilization) because they contact mucous membranes or nonintact tissue but do not penetrate tissues:

semicritical items

endoscopes, equipment for respiratory therapies are examples of:

semicritical items

contact but do not penetrate intact skin so they need to be clean but not highly disinfected:

noncritical items

bed linens, furniture, crutches, stethoscopes, blood pressure cuffs are examples of:

noncritical items

cleansing fomites to achieve levels of microbes low enough deemed safe for public health:

sanitization

kills bacteria:

bactericides

kills (inactivates) viruses:

viricides

kills fungi:

fungicides

____ agents inhibit growth but do not kill bacteria.

bacteriostatic

____ treatments inhibit the growth of fungi.

fungistatic

describes the progress and effectiveness of a particular antimicrobial protocol:

microbial death curve

specific microbial control protocols produce a constant rate of killing the target microbes so they are described in terms of the:

percentage killed

the amount of time it takes for a protocol to reduce a population by one order of magnitude (90%):

DRT

what does DRT stand for?

decimal reduction time

what is another term for decimal reduction time (DRT)?

d-value

microbial death is logarithmic. true or false?

true

microbial death is linear. true or false?

false

the ____ is easily observed using a semilog plot instead of an arithmetic one.

microbial death curve

one of the most common forms of microbial control:

heat

high temperatures kill cells by denaturing proteins by disrupting ____ bonds.

noncovalent

can sterilize heat-stable equipment (glass, metals) by applying high temperatures for extended periods of time:

ovens

using a bunsen burner or kill cells via combustion:

incineration

type of dry-heat sterilization:

incineration

often kills microbes in less time than dry-heat methods and may cause less damage than incineration or baking:

moist-heat sterilization

dry heat penetrates cells better than moist heat. true or false?

false

form of moist-heat sterilization control:

boiling

boiling can kill endospores. true or false?

false

boiling is more effective at high altitudes. true or false?

false

autoclaves rely most on ____.

moist-heat sterilization

uses temperatures about the boiling point of water (121°C) by employing high pressure (20 psi):

autoclaves

uses pressurized steam to effectively kill microbes, including endospores:

autoclaves

autoclaved along with the materials to be sterilized to ensure that the proper sterilization temperature has been reached:

indicators

one common type of indicator is the use of heat sensitive ____ which has white strips that turn black when the appropriate temperature is achieved during a successful autoclave run.

autoclave tape

another type of indicator that uses the endospores of geobacillus stearothermophilus to determine whether the endospores are killed by the process:

biological indicator spore test

another autoclave indicator that is a glass ampule containing a pellet that melts at the proper sterilization temperature:

diack tube

forms of microbial control for food that uses heat but does not render the food sterile:

pasteurization

what does HTST stand for?

high temperature short time

what does UHT stand for?

ultra high temperature

exposes milks to a temperature of 72°C for 15 seconds which lowers bacterial numbers while preserving the quality of the milk:

HTST pasteurization

exposes milk to a temperature of 138°C for 2 or more seconds:

UHT pasteurization

milk that undergoes ____ can be stored without refrigeration but the very high temperatures cause slight changes to the taste and smell.

UHT pasteurization