48) What compound was used to limit the presence of oxygen in the oxygen environ

Question

48) What compound was used to limit the presence of oxygen in the oxygen environmental factor lab? 49) State two environmental conditions that could induce the formation of endospores. 50) What general characteristics about a microbe did the Remel RapID test for? 51) True or False: Mechanical filtration is effective for removing all bacteria from a water sample when the pore size is 0.25 micrometers 52) What was the purpose of heating commercial beverages to 80 degrees Celsius? For full credit, use the correct term.

Explanation / Answer

48. Chemicals such as sodium bicarbonate and sodium borohydride are used to limit the presence of oxygen in the oxygen environmental factor lab. These chemicals react with water and produce hydrogen gas and CO2. The hydrogen gas combines with oxygen to produce water and hence the concentration of oxygen reduces.

49. The environmental conditions that induce the formation of endospores are

a. Very high or very low temperatures (also called extreme temperatures)

b. Exposure to radiation such as UV light

c. Very low or very high pH (also called extreme pH levels)

d. Extreme pressure

e. Exposure to the chemicals which are harmful to the microorganism

50. Characteristics of Remel RapID test are as follows:

a. This test can detect greater than 400 microbial pathogens in a short duration (that is only four hours) with high accuracy.

b. Inoculum will be inoculated in a dehydrated medium and after incubation, it detects coryneform Gram-positive bacilli, anaerobes, enterics, non-fermentors, streptococci, and yeast.

b. It is extremely simple with only one-time inoculation.

c. It requires only 4 hours of aerobic incubation

d. Extremely easy to interpret the results.

51. The answer is false

Mechanical filtration is not effective for removing all bacteria from a water sample when the pore size is 0.25 micrometers.

Reason: Mycoplasma, is a type of bacteria which has the capacity to pass through even the 0.2-micrometer membrane filters. Although 0.25-micrometer membrane filter is effective in removing most of the bacteria, it fails to filter mycoplasma. Hence, 0.25 is not enough to remove all bacteria from a water sample.

52. The heating of beverages to 80-degree celsius is called pasteurization. It destroys or reduces the pathogenic bacteria in beverages. It also reduces the undesirable enzymes.

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