TAMU FOOD BAC EXAM 3 WITH ALL
CORRECT & VERIFIED ANSWERS (UPDATED
TO PASS)
D value Correct answer-time in minutes at constant temperature necessary to initiate one.
(t2-t1)/log1-log2)
z value Correct answer-the thermal resistance constant (in degrees) temperature change in
degrees where by you can add to or subtract from the process to have a 10 fold change in the d value
of the organism.
z=deltat/(logDT2-DT1)
f value Correct answer-thermal death time.
time required at a constant termperature with known z-value to destroy a desired/ required number
of microbial cells.
Funiversal= @250degreesF(121.1C) with z=18
Ft=Dt(logn2-logn1)
Intrinsic Correct answer-Food chemistry-derived
• Food acidity/pH, aw, water content
• Physical state
• Antimicrobial presence, concentrations, types
Extrinsic Correct answer-These are incorporated into the physical processing in large measure
• Extraneous storage environment (ERH, O2 or atmosphere)
• Use of packaging in food processing (e.g., canning, sous vide)
Microbiological Correct answer-• Numbers and types of organisms targeted for inhibition,
inactivation
• Age of microbes and possible pre-exposures to sub-lethal stresses
• ID of a Pathogen of Concern (POC) or other pathogens
• Defined process lethality targets?
Thermal vs. Nonthermal Correct answer-Impacts on food characteristics, properties
• Organoleptic properties
• Consumer acceptability, palatability properties
• Physical, chemical degradation, changes by processing technology
• Energy demands of processing technology
• Equivalency in microbial destruction of differing processing technologies
• Thermal processing typically used as reference process
• Pathogen of concern may change with change in processing method
Non- Thermal Processing Correct answer-FDA and USDA both allow
non-thermal if the process can be validated food safety
pasteurization Correct answer-process, treatment, or combination thereof, that is
applied to food to reduce the most resistant microorganism(s) of public
health significance to a level that is not likely to present a public health risk
under normal conditions of distribution and storage.
-usually require refrigeration post process
, Thermal process Lethality Coefficients Correct answer-log (D/Dr)= -deltaT/z
z: Temperature change
providing 10-fold Dvalue
change
F: Time at constant
temperature to gain
desired microbial
lethality
High Hydrostatic Pressure Correct answer-log(D/Dr)= -deltaP/z
z: Pressure increase
providing 10-fold Dvalue
change
F: Time at constant
pressure to gain desired
microbial lethality
Pulsed Electric Field Correct answer-log(D/Dr)=-deltaE/z
z: EF field intensity
change providing 10-
fold D-value change at
constants temp.,
pressure
F: Time at constant EF
intensity to gain desired
microbial lethality
High Pressure Processing (HPP) Correct answer-very high pressure close to the bottom of the sea
(100-180MPa)
instantaneous pressure
High Hydro Static (HHP) Correct answer-single processor cyclical presurrization + decompression
Pressure Assisted Thermal Sterilization/ Processing Correct answer-accelrated process available by
controlled pressurization/ heating
High Pressure processed Correct answer-food come out in a brighter color and better tasting
because covalent bonds do not become effected.
Microbial inactivation(bacteria, yeasts, and molds) Correct answer-Enzyme/protein denaturation
• Ribosome destruction (replication inhibited)
Irreversible compression
• Inactivation can be enhanced by:
• Use of heat (PATS)
• Antimicrobials in food (acidulants, other antimicrobials)
Microbial Baro-Tolerance and Lethality Determination Correct answer-Dmpa: time (min) at
constant pressure producing a 1.0 log10- cycle reduction in microorganisms
Pulsed Electric Field Correct answer-Food passed through electrical
CORRECT & VERIFIED ANSWERS (UPDATED
TO PASS)
D value Correct answer-time in minutes at constant temperature necessary to initiate one.
(t2-t1)/log1-log2)
z value Correct answer-the thermal resistance constant (in degrees) temperature change in
degrees where by you can add to or subtract from the process to have a 10 fold change in the d value
of the organism.
z=deltat/(logDT2-DT1)
f value Correct answer-thermal death time.
time required at a constant termperature with known z-value to destroy a desired/ required number
of microbial cells.
Funiversal= @250degreesF(121.1C) with z=18
Ft=Dt(logn2-logn1)
Intrinsic Correct answer-Food chemistry-derived
• Food acidity/pH, aw, water content
• Physical state
• Antimicrobial presence, concentrations, types
Extrinsic Correct answer-These are incorporated into the physical processing in large measure
• Extraneous storage environment (ERH, O2 or atmosphere)
• Use of packaging in food processing (e.g., canning, sous vide)
Microbiological Correct answer-• Numbers and types of organisms targeted for inhibition,
inactivation
• Age of microbes and possible pre-exposures to sub-lethal stresses
• ID of a Pathogen of Concern (POC) or other pathogens
• Defined process lethality targets?
Thermal vs. Nonthermal Correct answer-Impacts on food characteristics, properties
• Organoleptic properties
• Consumer acceptability, palatability properties
• Physical, chemical degradation, changes by processing technology
• Energy demands of processing technology
• Equivalency in microbial destruction of differing processing technologies
• Thermal processing typically used as reference process
• Pathogen of concern may change with change in processing method
Non- Thermal Processing Correct answer-FDA and USDA both allow
non-thermal if the process can be validated food safety
pasteurization Correct answer-process, treatment, or combination thereof, that is
applied to food to reduce the most resistant microorganism(s) of public
health significance to a level that is not likely to present a public health risk
under normal conditions of distribution and storage.
-usually require refrigeration post process
, Thermal process Lethality Coefficients Correct answer-log (D/Dr)= -deltaT/z
z: Temperature change
providing 10-fold Dvalue
change
F: Time at constant
temperature to gain
desired microbial
lethality
High Hydrostatic Pressure Correct answer-log(D/Dr)= -deltaP/z
z: Pressure increase
providing 10-fold Dvalue
change
F: Time at constant
pressure to gain desired
microbial lethality
Pulsed Electric Field Correct answer-log(D/Dr)=-deltaE/z
z: EF field intensity
change providing 10-
fold D-value change at
constants temp.,
pressure
F: Time at constant EF
intensity to gain desired
microbial lethality
High Pressure Processing (HPP) Correct answer-very high pressure close to the bottom of the sea
(100-180MPa)
instantaneous pressure
High Hydro Static (HHP) Correct answer-single processor cyclical presurrization + decompression
Pressure Assisted Thermal Sterilization/ Processing Correct answer-accelrated process available by
controlled pressurization/ heating
High Pressure processed Correct answer-food come out in a brighter color and better tasting
because covalent bonds do not become effected.
Microbial inactivation(bacteria, yeasts, and molds) Correct answer-Enzyme/protein denaturation
• Ribosome destruction (replication inhibited)
Irreversible compression
• Inactivation can be enhanced by:
• Use of heat (PATS)
• Antimicrobials in food (acidulants, other antimicrobials)
Microbial Baro-Tolerance and Lethality Determination Correct answer-Dmpa: time (min) at
constant pressure producing a 1.0 log10- cycle reduction in microorganisms
Pulsed Electric Field Correct answer-Food passed through electrical
