MICROBIO 303 Test exam quizzes
and answers graded A+
Food production facilities - ANS✅✅Ensure quality, safety food through preventing contamination;
Facilities must keep surfaces clean and relatively free of microbes
Heat treatment - ANS✅✅Pasteurization, most common and reliable mechanism; Can alter flavor,
appearance of products
Irradiation - ANS✅✅approved to treat certain foods
Chemical additives - ANS✅✅Prevent spoilage, FDA regulates because of risk of toxicity
Chlorine - ANS✅✅sterilant (at high concentrations)
but used as a disinfectant (at low concentrations) in water
Water treatment facilities - ANS✅✅Has potentially saved 100,000's of lives by preventing
waterborne pathogens
What happens when chlorine reacts with naturally occurring organic chemicals? - ANS✅✅Form
disinfection by-products (DBPs), some DBPs linked to long-term health risks like cancer
What organism resists chlorine? - ANS✅✅Cryptosporidium parvum (parasite that causes diarrhea)
What is the goal of water treatment facilities? - ANS✅✅to minimize DBPs and C. parvum in treated
water, ensure drinking water free of pathogens
What is the choice of an effective antimicrobial procedure based on? - ANS✅✅- Type and number
of microbes
- Environmental conditions
- Risk of infection
- Composition of infected item
,Bacterial endospores - ANS✅✅(Bacillus and Clostridium) only extreme heat or chemical treatment
destroys them
Protozoan cysts and oocysts - ANS✅✅(Cryptosporidium) resistant to disinfectants, but destroyed
by boiling
Mycobacterium species - ANS✅✅waxy cell walls makes resistant to many chemical treatments -
need more toxic chemicals
Pseudomonas species - ANS✅✅may cause some HAI's and are resistant to and can actually grow
in some disinfectants
Non-enveloped viruses - ANS✅✅lack lipid envelope; more resistant to disinfectants
What can interfere with heat penetration and action of chemicals of the antimicrobial procedure? -
ANS✅✅Dirt, grease, and body fluids
What can influence effectiveness of the antimicrobial procedure? - ANS✅✅pH
Critical items - ANS✅✅Penetrate body tissues, must be sterile (no microbes)
Semi-critical instruments - ANS✅✅Contact mucous membranes, must be free of viruses and
vegetative bacteria, mucous membranes effective barriers against endospores
Example: Endoscopes and endotracheal tubes
Non-critical instruments - ANS✅✅Contact unbroken skin only, low risk of transmission
Example: Countertops, stethoscopes, blood pressure cuffs
Outbreak due to contaminated shots - ANS✅✅Fungal Meningitis 2012
Physical control methods - ANS✅✅•Heat
•Filtration
•Irradiation
, •High-pressure treatment
•Chemicals
Chemical control methods - ANS✅✅•Disinfectants
•Antiseptic
•Antibiotics
What is the most practical treatment for microbial control? - ANS✅✅Heat
Relatively fast, reliable, safe, and inexpensive
How can heat be used? - ANS✅✅Sterilant or disinfectant
Time and temperature dependent
What are the two types of heat? - ANS✅✅Moist heat and dry heat
What does moist heat do? - ANS✅✅Permanently denatures proteins
What are the three techniques of moist heat? - ANS✅✅Boiling
Pasteurization
Pressurized steam (autoclave)
What can and can't boiling reduce? - ANS✅✅Boiling is not sterilization; boiling kills/inactivates
viruses, bacteria, and protozoa; boiling does NOT kill prions and can only kill endospores if very high
temperature or long period of time
Pasteurization - ANS✅✅Does not sterilize; destroys/inactivates pathogens, reduces population of
spoilage organisms (with minimal changes to texture/flavor)
High-temperature-short-time (HTST) - ANS✅✅Most dairy products; Destroys all pathogenic
organisms, not all microbes; Milk: 72°C for 15 s, ice cream: 82°C for 20 s
and answers graded A+
Food production facilities - ANS✅✅Ensure quality, safety food through preventing contamination;
Facilities must keep surfaces clean and relatively free of microbes
Heat treatment - ANS✅✅Pasteurization, most common and reliable mechanism; Can alter flavor,
appearance of products
Irradiation - ANS✅✅approved to treat certain foods
Chemical additives - ANS✅✅Prevent spoilage, FDA regulates because of risk of toxicity
Chlorine - ANS✅✅sterilant (at high concentrations)
but used as a disinfectant (at low concentrations) in water
Water treatment facilities - ANS✅✅Has potentially saved 100,000's of lives by preventing
waterborne pathogens
What happens when chlorine reacts with naturally occurring organic chemicals? - ANS✅✅Form
disinfection by-products (DBPs), some DBPs linked to long-term health risks like cancer
What organism resists chlorine? - ANS✅✅Cryptosporidium parvum (parasite that causes diarrhea)
What is the goal of water treatment facilities? - ANS✅✅to minimize DBPs and C. parvum in treated
water, ensure drinking water free of pathogens
What is the choice of an effective antimicrobial procedure based on? - ANS✅✅- Type and number
of microbes
- Environmental conditions
- Risk of infection
- Composition of infected item
,Bacterial endospores - ANS✅✅(Bacillus and Clostridium) only extreme heat or chemical treatment
destroys them
Protozoan cysts and oocysts - ANS✅✅(Cryptosporidium) resistant to disinfectants, but destroyed
by boiling
Mycobacterium species - ANS✅✅waxy cell walls makes resistant to many chemical treatments -
need more toxic chemicals
Pseudomonas species - ANS✅✅may cause some HAI's and are resistant to and can actually grow
in some disinfectants
Non-enveloped viruses - ANS✅✅lack lipid envelope; more resistant to disinfectants
What can interfere with heat penetration and action of chemicals of the antimicrobial procedure? -
ANS✅✅Dirt, grease, and body fluids
What can influence effectiveness of the antimicrobial procedure? - ANS✅✅pH
Critical items - ANS✅✅Penetrate body tissues, must be sterile (no microbes)
Semi-critical instruments - ANS✅✅Contact mucous membranes, must be free of viruses and
vegetative bacteria, mucous membranes effective barriers against endospores
Example: Endoscopes and endotracheal tubes
Non-critical instruments - ANS✅✅Contact unbroken skin only, low risk of transmission
Example: Countertops, stethoscopes, blood pressure cuffs
Outbreak due to contaminated shots - ANS✅✅Fungal Meningitis 2012
Physical control methods - ANS✅✅•Heat
•Filtration
•Irradiation
, •High-pressure treatment
•Chemicals
Chemical control methods - ANS✅✅•Disinfectants
•Antiseptic
•Antibiotics
What is the most practical treatment for microbial control? - ANS✅✅Heat
Relatively fast, reliable, safe, and inexpensive
How can heat be used? - ANS✅✅Sterilant or disinfectant
Time and temperature dependent
What are the two types of heat? - ANS✅✅Moist heat and dry heat
What does moist heat do? - ANS✅✅Permanently denatures proteins
What are the three techniques of moist heat? - ANS✅✅Boiling
Pasteurization
Pressurized steam (autoclave)
What can and can't boiling reduce? - ANS✅✅Boiling is not sterilization; boiling kills/inactivates
viruses, bacteria, and protozoa; boiling does NOT kill prions and can only kill endospores if very high
temperature or long period of time
Pasteurization - ANS✅✅Does not sterilize; destroys/inactivates pathogens, reduces population of
spoilage organisms (with minimal changes to texture/flavor)
High-temperature-short-time (HTST) - ANS✅✅Most dairy products; Destroys all pathogenic
organisms, not all microbes; Milk: 72°C for 15 s, ice cream: 82°C for 20 s
