Explain the Decolourizing Agent - Ziehl-Neelsen Method?
Acid alcohol - a mixture of 95% ethanol and 3% HCI - is used for decolourization. Before decolourization, smear is allowed to cool to make waxy substances hardened. As primary stain is more soluble in cellular waxes than in decolourizing solution, acid-fast bacteria retain the primary stain. However, all non-acid fast bacteria loose primary stain because of the lack of cellular waxes.