Flashcards in Microbiology Deck (62)
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 ___
this traps the stain
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?
which phase is associated with waste production?
these are highly resistant to heat, easily dispersed, hard to destroy
what are 4 parts of spore?
core, cortex, coat, exosporium
outermost layer of spore, thin protein covering
loosely cross-linked peptidoglycan
contains core wall, cyto membrane, cyto, nucleoid, ribo
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
examples of bacteria that don't form spores
e coli and s. aureus
molds multiply by spores known as ___
these can't be cultured on plates and must be detected directly; single celled eukaryotes
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
contamination occurs primarily during ___
____ can eliminate pathogens
raw milk typically has ______ cfu/mL bacteria
alpha 1-4 polymers of galacturonic acid
beta 1-4 glucose polymers
alpha 1-6 glucose polymers that alter texture/flavour (slime)