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6 Cards in this Set
- Front
- Back
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How does test work?
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Certain bugs can reduce nitrate to nitrite or further to ammonium or molecular nitrogen. Nitrate broth is examined for presence of gas in durham tube
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What is the gas present in a Durham tube in a positive reaction (for non-fermenters)
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mixture of CO2 and N2
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Why is gas in the durham tube not necessarily a + result?
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Fermenters may produce gas from carbohydrate sources
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What is a + result? (primary)
Why does it occur. |
Red color produced
Nitirite ions are detected by reagent |
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If no color change what could be reasons?
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No nitrate reduction
Nitrate reduced past nitrite to ammonia or molecular nitrogen. |
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Why is zinc added to initially - tubes?
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Zinc reduces nitrates to nitrites. If pink color appears then that verifies that nitrates were not reduced. (negative test) If no color change then nitrates were reduced past nitrite stage.
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