Bacteriological Analysis of Water Flashcards
are a group of closely related, mostly harmless bacteria that live in soil and water as well as the gut of animals.
coliforms
is a hygienic indicator and high level of coliform counts generally indicates unsanitary condition or poor hygiene practices during or after food production
coliform count
These are organisms present in the environment and in the feces of all warm-blooded animals and humans
coliform bacteria
will not likely cause illness
coliform bacteria
coliform bacteria is
gram positive/negative
gram negative
oxygen requirement of coliform bacteria
facultative anaerobic
shape of coliform bacteria
rod shape
does coliform bacteria ferment lactose
yes
coliform ferments lactose to produce what
acid and gas
coliform bacteria ferments lactose to produce acid and gas within what variables
48 hours at 35oC
used as an indicator of sanitary quality of water or as a general indicator of sanitary condition in the food-processing environment.
detection of coliforms
three groups of coliform bacteria
total coliform
fecal coliform
E.coli (O157:H7)
indicates environmental contaminaton
total coliform
fecal coliform + e. coli =
fecal contamination
Are commonly found in the environment (soil or vegetation) and are generally harmless.
total coliform bacteria
If only __ ____ bacteria are detected in drinking water, the source is probably environmental
total coliform
____ contamination is not likely if total coliform is detected
fecal
Are a sub-group of total coliform bacteria.
fecal coliform bacteria
They appear in great quantities in the intestines and feces of people and animals
fecal coliform bacteria
its presence often indicates recent fecal contamination, meaning that there is a greater risk that pathogens are present than if only total coliform bacteria is detected
fecal coliform bacteria
It is a sub-group of the fecal coliform group.
e. coli
Most___ bacteria are harmless and are found in great quantities in the intestines of people and warm-blooded animals
e.. coli
straincauses a severe intestinal infection in humans
O157:H7
The presence of___ in a drinking water sample almost always indicates recent fecal contamination, meaning there is a greater risk that pathogens are present.
E. coli
___or treating contaminated drinking water with a ___destroys all forms ofE. coli, includingO157:H7.
boiling
disinfectant
It is a method for estimating the number of bacteria in a food or water sample.
most probable number method
In this technique, replicate portions of the original sample are cultured to determine the presence or absence of microorganisms in each portion.
most probable method
three phases of MPN
presumptive
confirmatory
completed
Almost all the methods used to detect E. coli
MPN
are enumeration methods that are based on lactose fermentation
total coliform or fecal coliform
It is used for detection and estimation of coliform in water sample.
presumptive test
broth in presumptive test
lactose containing broth medium
positive result of turbidity
turbidity of media and gas formation
equipment used for presumptive test
Durham’s tube
MPN table will be used to estimate the most probable number of viable cell.
presumptive test
Confirmed test is done to determine that the coliforms are of fecal origin or not.
confirmed test
Also determine if the isolated bacteria is E. coli or not.
confirmed test
are inoculated in Brilliant Green Lactose bile Broth (BGLBB) broth.
positive presumptive test
broth for confirmed test
Brilliant Green Lactose Bile Broth (BGLBB)
Positive BGLBB samples are inoculated in selective media like
eosin methylene blue agar
indicates the presence of E. coli.
green metallic sheen colonies
is performed on all samples showing a positive result in the confirmed test.
completed test
is e coli spore forming
no
The formation of gas in the fermentation tube and the presence of gram-negative, non-spore-forming, rod-shaped bacteria in the agar culture may be considered a satisfactorily ___ test
completed
1 mpn = __ cfu = ___ viable cell
1 cfu
1 viable cell
presuumptive test complete equipment
injective tube
durham tube
presumptive test kind of strength
5 double strength
10 single strength
doube the concentration of lactose broth used to test for coliform organisms in water
double strength
how many water sample is placed in double strenth
10 ml
how many water ml is placed in SS tubes (both amount)
1 ml
0.1 ml
to confirm strain of e. coli, it has to undergo
antigen-antibody test
