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WorksheetsMicrobial growth curve
Total questions: 22
Worksheet time: 53mins
Give any Two example of mild thermal processing ________&________(ALL CAPS - DIVIDE WITH COMMA NO SPACES)
(a)
Examples of Heat resistant enzymes ________&________(ALL CAPS DIVIDE BY COMMA NO SPACE)
(a)
Which describes the level of microbial destruction obtained by thermal treatment?
F○ value
Thermal death time
D value
Z value
________ relates the resistance of an organism to differing temperatures.
F value
Thermal death time
Z value
D value
_________ is defined as the time taken at a given temperature to eliminate at least 90% of the exposed microorganisms
F value
Thermal death time
D value
Z value
which of the following is spore forming thermophilic anaerobe ?
B.sterothermophilus
C.thermosaccharolyticum
C.sporogenes
Desutfomotomaculum nigrificans
which of the following blanching works in two stage process and results in higher efficiency?
Blancher cooker
Pipe blancher
steam blancher
Individual quick blanching
which of the following statements are right, regarding Testing of the Effectiveness of Blanching
Peroxidase enzyme is not in itself implicated in degradation
guaiacol solution and hydrogen peroxide solution are added to detect the peroxidase
Peroxidase is is relatively heat resistant and easily detected.
observing the development of a Red colour indicating peroxidase activity
(a) is a naturally occurring enzyme in raw milk with a similar D value to heat-resistant pathogens and so is routinely used as an indicator of adequate pasteurisation.( ALL SPACE GIVE SPACE IF NESSESSARY)
organisms that can survive exposure to relatively high temperatures but do not necessarily grow at these temperatures
Thermophilic
Mesophilic
psychrophiles
none of the above
In Steam tunnel Pasteurizer, the temperatures in the heating zones may be controlled depending on the amount of _________
water
pH
air
none of these
“Commercial sterility” - Identify the wrong statement
Its the complete destruction of all the microorganisms in the product
Most heat resistant pathogen is Clostridium botulinum.
Most heat-resistant (non-pathogenic) spoilage microorganisms are Bacillus stearothermophilis and Clostridium thermosaccharolytom
canning will come under UHT or aseptically processed sterilization
Simple small autoclaves are ____________, Larger autoclaves are __________(HORIZONTAL,VERTICAL)
(a)
D value is also known as
Decimal reduction time
Thermal death time
Decimal reduction point
none
“botulinum cook” time and temperature
12 mins - 121
4 min - 121
0.21 mins - 121
2.5 min - 121
106 spores of Bacillus stearothermophillus are present we want it to reduce to 0.1 spores - how much log reduction cycle has to happen
5D
12D
4D
7D
1000 Clostridium spores are present in the sample, we are giving 1010C to reducing those spore to 1- how much time needed ? ( calculate the D value - You already know the z value and D value for 121oC )
21
12
42
63
A product is held at a temperature of 118°C for a period of 12 minutes and L value is 0.49min, How much time required if same product held at 1210C ? ( Hint- calculate F value using the values)
6min
4.9 mins
4.6 mins
5.9 mins
The portion of the growth curve where rapid growth of bacteria is observed is known as ____________
Lag phase
Log phase
Stationary phase
Death phase
In which of the following phase secondary metabolites are produced during growth?
Lag phaseb
Log/Exponential phase
Stationary phased
Death phase
Which phase shows the reproduction rate equal to the equivalent death rate?
Log phase
Stationary phase
Death phase
Lag phase
The average size of the cells in the exponential phase is ___________
larger than the initial size
smaller than the initial size
equal to the initial size
maybe smaller or larger than the initial size
