Microbiology Flashcards
what are the three outcomes of microbes in food?
pathogenesis, spoilage, preservation
What are characteristics of colony morphology? (macroscopic)
form, margin, elevation, size, pigment, optical characteristics, texture
what are the major cell morphologies? (microscopic)
cocci, rod (bacillus), spirillum, spirochetes, appendaged, filamentous
gram positive stains ___, gram negative stains ___
purple; pink
this traps the stain
peptidoglycan
what are the 4 phases of bacterial growth?
lag, exponential, stationary, death
what is the lag phase?
interval between when culture is inoculated and when growth begins
what is the most desirable stage for study of bacteria for enzymes?
exponential phase
which phase is associated with waste production?
stationary phase
these are highly resistant to heat, easily dispersed, hard to destroy
endospores
what are 4 parts of spore?
core, cortex, coat, exosporium
outermost layer of spore, thin protein covering
exosporium
loosely cross-linked peptidoglycan
cortex
contains core wall, cyto membrane, cyto, nucleoid, ribo
core
core is high in ____ acid, and ____ proteins
dipicolinic; small acid soluble
cytoplasm in endospore core contains ___% of water found in vegetative cell, pH is __ unit lower
10-25; 1
examples of bacteria that don’t form spores
e coli and s. aureus
molds multiply by spores known as ___
conidia
these can’t be cultured on plates and must be detected directly; single celled eukaryotes
protozoan parasites
obligate parasites that are host specific, transmitted fecal/orally
food borne virus
sources of microbes in food?
soil/water, plants, food utensils, GI, mamary tissue, food handlers, animal feed, animal hide, air/dust
biggest source of microbes in foods?
soil and water
fresh cut meats have ___ cells/gram microbes, comminuted (ground up) meats have ____ cells/gram
10^3; 10^6
contamination occurs primarily during ___
harvesting
____ can eliminate pathogens
composting
raw milk typically has ______ cfu/mL bacteria
100-100 000
alpha 1-4 polymers of galacturonic acid
pectin
beta 1-4 glucose polymers
cellulose
alpha 1-6 glucose polymers that alter texture/flavour (slime)
dextrans
do microbes target proteins or carbs first?
carbs
what are examples of biogenic amines?
cadaverine, putrescine
what are factors that affect microbial growth?
nutrients, water activiy, temp, o2, pH, physical props (SA, exudates, natural barriers), applied ingredients (nitrite, salt, sugar, smoke, acids, spices)
what is hurdle approach?
multiple parameters are employed to obtain growth inhibition (combine)–>less extreme
milk at pH ___ form gel, at pH __ forms precipitate of protein
5.2; 4.6
production of yogurt takes __ hr
6
making sauerkraut, add __% salt
2.5
infective dose of e. coli and salmonella is ____, for shigella is ____
10^5; 10
what are the 4 diff pathogenic microorganisms?
bacteria, fungi, parasites, viruses
fecal oral transmission routes
hands/person to person; insects, water, crops, soil
fever caused by ___
pyrogen
viruses to know?
hep A, noro, rota
this bacteria is everywhere
listeria
rice contains ____ toxin
cereulide
aspergillus flavus creates ___
mycotoxins
secondary metabolites that are “fungal poison”
mycotoxins
produces alkaloid toxin, that causes hallucination, known as “St. Anthony’s fire”
claviceps
if grain has > ___% C. purpurea by weight it is considered ___
0.3; ergoty
yellow rice caused by ___ and causes severe ___ damage
penicillium; liver
Turkey X disease caused by _____
aflatoxin
what is ATA?
Alimentary Toxic Aleukia, consumption bread contaminated w/ trichocenes from Fusarium–>cause dermal necrosis, hemorrhage, bone degrade
What is e.coli that produces toxin?
EHEC; esp O157
what are EHEC symptons?
Hemolytic uremic syndrome (hemolytic anemia, thrombocytopenia, renal fail), bloody diarrhea, nausea/vomiting, fever (rare), severe cramps, thrombotic thrombocytopenia purpura
incubation of EHEC is ___ days, symptoms last _____ days
4; 7-10
ice can contain ____ virus
hep A
virus common on cruise ships that has long latency period
norovirus
proteins that are very difficult to kill; examples include scrapie, BSE, chronic wasting disease
prions
what does HACCP stand for?
Hazard Analysis Critical Control Point System
what are trends in processing?
centralization; greater distances and increased holding times
what are the 7 principles of HACCP?
1) assess hazards 2) determine critical control points 3) establish critical limits 4) establish procedures monitor CCP 5) establish corrective actions 6) establish procedures that verify plan working 7) effective record/doc system
what is FSEP?
Food safety enhancement program, include HACCP but extends beyond to entire food enviro before HACCP implementation, in CFIA
what are GMPs?
Good Manufacturing Practices
FSEP and HACCP now required in all federally registered ______ establishments
meat/poultry
