ANSC 326 Exam 1 Questions With
Accurate Answers
microbiology - ANSWER artificial sub discipline of biology based on size
food microbiology - ANSWER studies microbes that grow in food
Louis Pasteur - ANSWER 1850 demonstrated that microbes complete lactic and
ethanol fermentation
early food preservation methods - ANSWER probably accidental, sun
dried/salted/frozen
Fermented food became a thing around - ANSWER 4000 BCE
Robert Koch - ANSWER Koch's postulate is about establishing a causal
relationship between a pathogen and an illness
ecology - ANSWER studies interaction of organisms and factors in a niche
Is food an ecosystem? - ANSWER yes
viable vs. culturable - ANSWER viable means alive, culturable means detectable
by testing methods
ecology applied to microbiology - ANSWER study of interactions between
chemical/physical/structural aspects of a niche
niche - ANSWER could be a food product, processing surface, biofilm (ex- water
trough or water column)
MPN - ANSWER most probable number, estimate of number of organisms in a
sample with low levels
plate counts - ANSWER directly enumerating organisms to count bacteria, can
be found at different temperatures/atmospheres
quantitative - ANSWER directly counting, uses 1 cell per colony rule
qualitative - ANSWER detection in culture (ex- salmonella present or not)
, semi-quantitative - ANSWER an estimate (ex- MPN)
selective media - ANSWER nourish growth of some, inhibit growth of other
microbes
D value - ANSWER time it takes to kill 90% of the population or reduce by 10 fold
(1D=90% reduction in population), measure of heat resistance in spores
zero tolerance - ANSWER no tolerance for the detection of a certain
microorganism on ready-to-eat product (ex- bologna)
cell injury - ANSWER lost ability to grow on selective media because of damaged
membrane, grow only on nonselective media, can still cause illness if consumed
VBNC - ANSWER viable but not culturable, caused by lack of nutrients, cannot
be cultured on any medium
3 reasons why cell injury is a threat - ANSWER easy to overestimate how good a
process is, could escape detection and cause illness, could escape detection
and underestimate microbial levels
cell repair - ANSWER regain full vitality and capacity to cause disease
causes of cell injury - ANSWER heating, freezing, detergent
resuscitation of VBNC cells - ANSWER increase in cell levels takes time, it is not
immediate
quorum sensing - ANSWER used to determine if bacteria population is ready for
an action, increased concentration-->diffuse across membrane-->bind-->action
carried out, the extracellular concentration increases with bacteria
4 criteria for quorum sensing - ANSWER signal specific to an event, signal
accumulates extracellularly, unique response triggered when signal diffuses
and binds, response beyond normal activity
signal transduction - ANSWER signal binds receptor enzyme, enzyme changes
orientation and triggers response
planktonic - ANSWER free swimming
sessile - ANSWER fixed on surface or in a film
biofilm - ANSWER aggregation of all kinds of cells, sessile, cells here are more
tolerant to heat/chemicals
Accurate Answers
microbiology - ANSWER artificial sub discipline of biology based on size
food microbiology - ANSWER studies microbes that grow in food
Louis Pasteur - ANSWER 1850 demonstrated that microbes complete lactic and
ethanol fermentation
early food preservation methods - ANSWER probably accidental, sun
dried/salted/frozen
Fermented food became a thing around - ANSWER 4000 BCE
Robert Koch - ANSWER Koch's postulate is about establishing a causal
relationship between a pathogen and an illness
ecology - ANSWER studies interaction of organisms and factors in a niche
Is food an ecosystem? - ANSWER yes
viable vs. culturable - ANSWER viable means alive, culturable means detectable
by testing methods
ecology applied to microbiology - ANSWER study of interactions between
chemical/physical/structural aspects of a niche
niche - ANSWER could be a food product, processing surface, biofilm (ex- water
trough or water column)
MPN - ANSWER most probable number, estimate of number of organisms in a
sample with low levels
plate counts - ANSWER directly enumerating organisms to count bacteria, can
be found at different temperatures/atmospheres
quantitative - ANSWER directly counting, uses 1 cell per colony rule
qualitative - ANSWER detection in culture (ex- salmonella present or not)
, semi-quantitative - ANSWER an estimate (ex- MPN)
selective media - ANSWER nourish growth of some, inhibit growth of other
microbes
D value - ANSWER time it takes to kill 90% of the population or reduce by 10 fold
(1D=90% reduction in population), measure of heat resistance in spores
zero tolerance - ANSWER no tolerance for the detection of a certain
microorganism on ready-to-eat product (ex- bologna)
cell injury - ANSWER lost ability to grow on selective media because of damaged
membrane, grow only on nonselective media, can still cause illness if consumed
VBNC - ANSWER viable but not culturable, caused by lack of nutrients, cannot
be cultured on any medium
3 reasons why cell injury is a threat - ANSWER easy to overestimate how good a
process is, could escape detection and cause illness, could escape detection
and underestimate microbial levels
cell repair - ANSWER regain full vitality and capacity to cause disease
causes of cell injury - ANSWER heating, freezing, detergent
resuscitation of VBNC cells - ANSWER increase in cell levels takes time, it is not
immediate
quorum sensing - ANSWER used to determine if bacteria population is ready for
an action, increased concentration-->diffuse across membrane-->bind-->action
carried out, the extracellular concentration increases with bacteria
4 criteria for quorum sensing - ANSWER signal specific to an event, signal
accumulates extracellularly, unique response triggered when signal diffuses
and binds, response beyond normal activity
signal transduction - ANSWER signal binds receptor enzyme, enzyme changes
orientation and triggers response
planktonic - ANSWER free swimming
sessile - ANSWER fixed on surface or in a film
biofilm - ANSWER aggregation of all kinds of cells, sessile, cells here are more
tolerant to heat/chemicals
