quiz 3 Flashcards
which conditions can endospores stand?
heat, radiation, toxic chemicals
what are endospores?
clostridium and bacillus, gram positive rods
How did we isolate endospore forming bacteria?
endospores are heat resistant
Why did we grow endospores aerobically and anaerobically?
To isolate both clostridium and bacillus
endospore stain
malachite green dye
What does the glucose ferment tube test?
Test strain’s ability to produce gas and acid fro glucose
What is the methyl red test?
pH less than 4.4 signifies a positive test, that an organism produced high levels of acid from fermentation of glucose.
What is the voges-proskauer test?
acetonin test, do organisms use butandeiol fermentation to ferment glucose? red is a positive result
What is the point of the nutrient broth test?
Because we put it in the 50C water bath, it tests the organisms strain tolerance
Why the nutrient +7% NaCl broth?
Tests for ability to grow in high salt content
Why milk agar?
See if can degrade casein
Why starch agar?
degrade starch?
Why do pseudomonads turn fluorescent?
Under nutrient limiting conditions, they can produce a soluble pigment that can diffuse into growth medium
What kind of respires are pseudomonads?
obligate respirers that use oxygen as a terminal electron acceptor
What does the oxidase test test for?
The presence of cytochrome C oxidase, in etc.
How is bread leaving achieved?
Sugars are converted to CO2 and ethanol.
What bacteria is in sourdough starter?
wild Yeats and lactic acid bacteria, lactobacillus
What does adding salt to saurkraut do?
it draws out sugar containing juices so they can be fermented more easily, and the high salt concentration inhibits the growth of most microorganisms.
What bacteria grow best in high salt?
lactic acid bacteria
What is ecological succession?
changes in the species present within a community over time
What is the common cause of ecological succession?
selective pressure
How is the final product preserved?
high salt and high acidity inhibits the growth of potential spoilage
Why is it unusual that lactic acid bacteria are catalase negative?
They are grown in the presence of oxygen, nut use peroxidase to to eliminate toxic hydrogen peroxide.
What is an aerotolerant anaerobe?
anaerobes metabolically grown in the presence of oxygen
