Study Set Content:
SUGAR FERMENTATION
Principle/Inference
Microorganisms are able to go about fermentation In the presence of certain sugar producing an
acid and/or gas.
Microorganisms are able to go about fermentation In the presence of certain sugar producing an acid and/or gas. (blank) is produced together with some sugar alcohols.
CO2
Specific sugars upon fermentation ascertain to differentiate clearly not only the
enteric bacteria
Specific sugars upon fermentation ascertain to differentiate clearly not only the enteric bacteria but also other
species or genera
SUGAR FERMENTATION Reagent
Andrade’s Indicator
A broth containing sugar (blank) is inoculated with bacterial colony then incubated
lactose
A broth containing sugar (lactose) is inoculated with bacterial colony then incubated for
24-48hrs
SUGAR FERMENTATION POSITIVE
A broth containing sugar (lactose) is inoculated with bacterial colony then incubated for 24-48hrs. Andrade’s indicator is added and result shows a change in
pH
A broth containing sugar (lactose) is inoculated with bacterial colony then incubated for 24-48hrs. Andrade’s indicator is added and result shows a change in pH as indicated by
pink formation and gas formation (bubbles)
A broth containing sugar (lactose) is inoculated with bacterial colony then incubated for 24-48hrs. Andrade’s indicator is added and result shows a change in pH as indicated by pink formation and gas formation (bubbles) In the durham’s tube. (blank) is an organisms that can ferment lactose.
E. coli
SUGAR FERMENTATION NEGATIVE
A broth containing sugar (lactose) is inoculated with bacterial colony then incubated for 24-48hrs. Andrade’s indicator is added and result is (blank) pH
neutral
A broth containing sugar (lactose) is inoculated with bacterial colony then incubated for 24-48hrs. Andrade’s indicator is added and result is neutral pH as indicated by
no color change and no gas formation
is an organism that cannot ferment lactose.
Salmonella
tube in sugar fermentation
durham's tube
B. H2S principle
Presence of H2S in certain bacteria will lead to formation of
Carbon dioxide and Ferrous Sulphide
TSI Principle/Inference
> some can ferment (blank) exclusively
glucose
> some ferments either
lactose or sucrose
> gas formation (bubbles) is indicative production of
H2S gas
The agar butt/slant contains three sugars
(Glucose, sucrose, lactose)
> (H2S)
Ferrous Sulfate
