BSC 242- Lab Exam 3
2026-2027
Expert-Verified Questions and Answers
(With A+ Grades Guarantee)
, Sterilization any process that kills or destroys all forms of life, including bacterial endospores
-Sterilization is usually achieved by physical methods
Disinfection -any process that reduces a microbial population on an inanimate surface to an
acceptable level
-Disinfection is achieved using a disinfectant (usually a chemical).
Antisepsis -any process that reduces a microbial population on living tissue to an acceptable
level
-Antisepsis is achieved using an antiseptic (usually a chemical).
"-cidal" a suffix used to identify agents that kill or destroy microorganisms
-For example, bacteriocidal agents kill bacteria, while fungicidal agents kill fungi
(yeasts and molds).
"-static" a suffix used to identify agents that do not kill, but only inhibit the growth of
microorganisms
-When the agent is removed, the microorganism may resume growth.
-For example, bacteriostatic agents inhibit the growth of bacteria.
Physical methods of microbial control 1. heat
2. radiation
3. filtration
1. heat (3 types) 1. dry heat
2. moist heat
3. pasteurization
1. dry heat -kills organisms by oxidizing proteins and lipids.
-High temperatures and long heating times are required to heat-sterilize items
-For example, 2 hours at 160°C or 1 hour at 170°C. Because of the high
temperatures, heat sterilization is usually applied to glassware and metal objects
2. moist heat -kills organisms by denaturing proteins and membrane lipids
-Moist heat is a method of sterilization that uses steam under pressure
-Because of the moisture, heating times and temperatures are not as long or high
as with dry heat. The process is called autoclaving and can be applied to glass,
metal, some plastics and liquids.
-The typical operational parameters are 121°C at 15 pounds per square inch (psi)
for 15 minutes
3. pasteurization -a method of disinfection that uses gentle heating.
-For example, 62.9°C for 30 minutes or 71.6°C for 15 seconds.
-is applied to food products for which extreme temperatures may alter food taste
2. radiation (2 types) 1. ionizing
2. non ionizing
1. ionizing x-, γ- and cosmic rays
-usually used for sterilization
-It induces double-stranded breaks in the DNA molecule, damage that cannot be
repaired since a template is absent
-The effectiveness of the radiation is directly proportional to the amount of DNA
present
--Thus, the effectiveness is as follows: viruses < fungi < spores < G+ < G-
(increasing susceptibility)
-has good penetrating power and can be used to sterilize pre-packaged items
2026-2027
Expert-Verified Questions and Answers
(With A+ Grades Guarantee)
, Sterilization any process that kills or destroys all forms of life, including bacterial endospores
-Sterilization is usually achieved by physical methods
Disinfection -any process that reduces a microbial population on an inanimate surface to an
acceptable level
-Disinfection is achieved using a disinfectant (usually a chemical).
Antisepsis -any process that reduces a microbial population on living tissue to an acceptable
level
-Antisepsis is achieved using an antiseptic (usually a chemical).
"-cidal" a suffix used to identify agents that kill or destroy microorganisms
-For example, bacteriocidal agents kill bacteria, while fungicidal agents kill fungi
(yeasts and molds).
"-static" a suffix used to identify agents that do not kill, but only inhibit the growth of
microorganisms
-When the agent is removed, the microorganism may resume growth.
-For example, bacteriostatic agents inhibit the growth of bacteria.
Physical methods of microbial control 1. heat
2. radiation
3. filtration
1. heat (3 types) 1. dry heat
2. moist heat
3. pasteurization
1. dry heat -kills organisms by oxidizing proteins and lipids.
-High temperatures and long heating times are required to heat-sterilize items
-For example, 2 hours at 160°C or 1 hour at 170°C. Because of the high
temperatures, heat sterilization is usually applied to glassware and metal objects
2. moist heat -kills organisms by denaturing proteins and membrane lipids
-Moist heat is a method of sterilization that uses steam under pressure
-Because of the moisture, heating times and temperatures are not as long or high
as with dry heat. The process is called autoclaving and can be applied to glass,
metal, some plastics and liquids.
-The typical operational parameters are 121°C at 15 pounds per square inch (psi)
for 15 minutes
3. pasteurization -a method of disinfection that uses gentle heating.
-For example, 62.9°C for 30 minutes or 71.6°C for 15 seconds.
-is applied to food products for which extreme temperatures may alter food taste
2. radiation (2 types) 1. ionizing
2. non ionizing
1. ionizing x-, γ- and cosmic rays
-usually used for sterilization
-It induces double-stranded breaks in the DNA molecule, damage that cannot be
repaired since a template is absent
-The effectiveness of the radiation is directly proportional to the amount of DNA
present
--Thus, the effectiveness is as follows: viruses < fungi < spores < G+ < G-
(increasing susceptibility)
-has good penetrating power and can be used to sterilize pre-packaged items
