Sugar Broths
The BCP in sugar broths is a pH indicator which turns from purple to yellow in response to the production of this.
Acid
These are the four tests in the IMViC series.
Indole, methyl red, Voges-Proskauer (VP), citrate
Cells build this up as a result of normal metabolism and in high amounts can be toxic.
Hydrogen peroxide
Electron transport chain
This clear zone indicates prevention of bacterial growth.
Zone of inhibition
These usually kill microorganisms on inorganic surfaces.
Disinfectants
Bacterial production of hydrogen sulfide often occurs in these places.
Anaerobic environments
Urease enzyme breaks down urea into these compounds.
Ammonia and carbon dioxide
Nitrates can be reduced by some bacteria all the way down to these two gases.
Ammonia and nitrogen gas
Enteropluri tubes are read by generating this from the results of the tests.
A 5 number code
This test is used to determine the number of viable bacteria in a food sample.
This is small tube inside of a sugar broth that traps gases.
Durham tube
This reagent needs to be added to tryptone broth to determine the presence of indole.
Kovac's reagent
This enzyme can be utilized by certain bacteria to breakdown hydrogen peroxide.
Catalase
Enteric Gram-negative bacteria are usually oxidase ___.
Negative
The large this is, the more effective an antibiotic is against a bacterium.
Diameter of the zone of inhibition
These kill microorganisms on organic surfaces such as skin or other tissues.
Antiseptics
In a peptone iron agar deep, the black precipitate is this.
Ferrous sulfide
Urea broth has this pH indicator in it.
Phenol red
This bacterium can completely reduce nitrates down to nitrogenous gases.
Pseudomonas
Enteropluri tests are typically only useful for this kind of bacterium.
Gram-negative and oxidase negative
Raw ground beef must have less than this amount of bacteria before cooking or other preparation to be considered safe to eat.
100,000 CFUs/gram
What three different sugars did we use in the lab's broths?
Glucose, lactose, sucrose
Methyl red and VP, which are both in the same broth, are testing for these things respectively.
Mixed acids and mixed alcohols/other byproducts
This indicates the presence of catalase in a bacterium when expose to hydrogen peroxide.
Bubbling
This Gram-negative rod is usually oxidase positive.
Pseudomonas
Whether a bacterium is this or this can sometimes, but not always, affect its susceptibility or resistance to different antibiotics.
Gram-positive or Gram-negative
These kill bacteria within the body.
Antibiotics
Some bacteria can make hydrogen sulfide through the oxidation of this amino acid.
Cysteine
Urea broth turns from orange to pink due to this.
Increased pH
This bacterium can reduce nitrates to nitrites.
Escherichia (such as E. coli)
There are this many tests contained within an Enteropluri tube.
15
Name at least two common bacteria tested for in food and that can cause food poisoning or other gastrointestinal illnesses.
E. coli, Salmonella, Campylobacter, Shigella, Clostridium, etc.
If you have a sugar broth that has turned yellow and there are no bubbles in the Durham tube, what has been produced?
Acid
A positive citrate test is indicated by what color present in the agar?
Blue
These plates can be used to sample different surfaces for bacteria.
RODAC plates
Some bacteria can make hydrogen sulfide from the reduction of this compound.
Thiosulfate
These kinds of bacteria are the most common urease producers.
Gram-negative rods
If a nitrate broth does not turn red after adding the nitrate reagents but does when zinc powder is added, what is the result?
Negative for nitrate reduction
We used this technique for this lab to determine the number of bacterial CFUs/mL for our meat samples.
Pour plating
If you have a sugar broth that has turned yellow with bubbles in the Durham tube, what products have been made?
Acid and gas
Which tests in an IMViC series are positive and negative if you have the IMViC signature +-++?
Indole positive, methyl red negative, VP positive, citrate positive
The spreading of ferrous sulfide through an iron agar deep indicates this trait of bacteria.
Motility
If a nitrate broth does not turn color after adding both the nitrate reagents and zinc powder, what is the result?
Positive for nitrate reduction down to ammonia and nitrogen gas
This is the range of colonies on a plate used for calculating CFUs/mL and any higher or lower than this is considered impractical for calculation.
25 to 250 colonies