mbio quiz 58292984690

what temperature does lactic acid grow at?

40-45 celcius

what does lactic acid do in the production of sauerkraut?

Leuconostoc sp. produces organic acids which lowers the pH to about 3.5 and the chemical diacetyl

why is NaCl added to the shredded cabbage in making sauerkraut?

NaCl is provided to give the shredded cabbage optimum environmental conditions for the growth of desired fermentating bacteria

yogurt fermentation equation

amount of ml * amount of people e.g. 50 mL * 36 people

what is fermentation?

anaerobic process that produces gas, alcohol, yogurt, sauerkraut

what is the purpose of adding corn sugar to each sterile bottle before adding the beer and capping?

beer is produced when sugar in plants are fermented by years in the absence of oxygen, sugars are metabolized to ethanol and CO2

how is saeurkraut fermented?

by a group of bacteria (leuconostoc and lactobacillus)

how is yogurt fermented?

by warm milk using lactic acid producing bacteria

sauerkraut fermentation equation

cabbage (g) * 0.0025 = salt

describe how you would show that streptococcus and lactobacillus are present in commercial yogurt?

gram stain (both are positive), pH levels because they both release lactic acid so they should be below 7, and thy are oxidase and catalase-negative too

if yogurt were gram stained, what results would indicate the yogurt is contaminated?

if it was red (gram negative_ it would indicate contamination

calculation for colony forming units

number of colonies/(amount plated)(dilution)

name an ingredient for beer fermentation

pre-hopped malt powder

what does fermentation do?

preserve food products

name an ingredient for sauerkraut fermentation

salt, cabbage

how is beer and wine fermented?

sugars in plants are fermented by yeast

why is water-filled plastic bag used to cover the cabbage in the production of sauerkraut?

the cover inhibits the entry of oxygen into the mixture and allows the anaerobic fermentation to occur

what would happen if a plain, solid rubber stopper was used to tightly seal the beer fermentation vessel?

there needs to be an attached length of latex tubing. Without that in addition, a regular stopper wont produce gas during fermentation wont bubble off water

how do leuconostoc and lactobacillus produce sauerkraut flavor?

they grow sequentially; leuconostoc produces organic acids which lowers the pH to 3.5 and then lactobacillus is followed which produces more acid and lowers the pH to 3.0

name an ingredient for yogurt fermentation

whole milk