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Principle
- Nitrate broth is composed of peptone, meat extract (equivalent to beef extract), and sodium nitrate. Peptone and meat extract provide nitrogen, amino acids, carbon, and other essential nutrients.
- Potassium nitrate is a source of nitrate. The nitrate-reducing bacteria convert nitrate to nitrites. The produced nitrites are detected by adding α-naphthylamine. In an acidic environment, the nitrites react with alpha-naphthylamine to produce a pink or red color.
- While, nitrate-negative organisms, are unable to reduce nitrates, and yield no color after the addition of α-naphthylamine. Nitrate-negative reactions are tested with zinc dust to confirm the presence of unreduced nitrate.
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