Chapter 8, Problem 1SA

Molds are used in the manufacture of several fermented foods? Which molds are used in each of these foods and for what purpose (s)? What precautions are needed while using a mold strain in food fermentation? Please support your answers with examples and be thorough in your answer.

A stool specimen of a patient with severe diarrhea was cultured in a series of specialized media for isolation of enteric organisms. The cultures yielded three isolates that were species of Salmonella, Shigella, and Escherichia. Explain why the Hydrogen sulfide production test would be diagnostically significant.

You saw no color change in both the first step and second step of the Nitrate Reduction test. What is the result of this experiment? Also, explain what happens when an excessive amount of zinc is added in the second step of this test.

True or false. Based on the above results none of the above cultures showed motility.  View attached photo.

‘Practical techniques used to identify unknown microorganisms’ You should include the types of tests you would use and how to interpret the results. You do not have to include a step-by-step guide to each of the practical techniques, but rather information could include background, reasoning and/or expected results.

True or false  A spectrophotometer is used to directly count the number of cells in a liquid culture media.

Which of these microbial structures is the most difficult to kill when attempting to sterilize instruments?     bacterial spores     Mycobacterium pneumoniae     protozoal cysts     fungal spores

Nitrate reduction to nitrite is indicated by the formation of a pink to red colour after addition of nitrate test reagent. However, if a culture does not produce a colour change several posibilies exist. Explain.

Tell me three things about how cultures are handled in a clinical laboratory.