Six disinfectants are in routine use, each with a different spectrum and a different set of
cautions. Formalin in particular is classed as carcinogenic and hazardous — mask, coat,
gumboots and gloves are mandatory, not advisory.
Disinfectants
| Disinfectant | Working strength | Action and cautions |
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| Sodium hypochlorite | 0.02–0.05 % in field; 0.2 % for eggs | Broad spectrum against viruses, bacteria, fungi and mycobacteria; the routine in-crop disinfectant. |
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| Formalin | 2 % (1 part formalin : 17 parts water) | Supplied as 36 % formaldehyde. Works only in a sealed room above 20–25 °C and 70 % RH. Classed as carcinogenic and hazardous; mask, coat, gumboots and gloves mandatory. |
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| Bleaching powder | 2 % in 0.3 % slaked lime as spray; 5 % for appliances | Requires 30 % active chlorine. Acts by nascent oxygen and released chlorine. Effective only on wet surfaces; store sealed and dry. |
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| Slaked lime | 0.3 % solution; 9:1 with bleaching powder for dusting | Maintains hygiene and controls bed humidity. |
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| LAHDOI | 1 g per litre | Institute formulation against muscardine. Spray plants and drench soil 7 days before brushing, then every 15 days until maturation; safe during rearing. Prevents infection up to about 70 %, cost–benefit 1 : 3.5 against 1 : 0.86 in control. Use within six months of packing. |
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| Chlorine dioxide | 2–5 % with 0.5 % slaked lime | Sanitech or Serichlor at 20,000 ppm, activated at point of use. Effective across a broad pH range, about 2.5 times as effective as chlorine and 50 times as effective as hypochlorites; least corrosive at normal strength. |
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Preparation and application
| Solution | Preparation |
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| 2 % formalin | Divide the volume required by 18 for the quantity of formalin; add 17 parts water to 1 part formalin. |
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| 100 L of 2 % bleaching powder in 0.3 % slaked lime | Paste 2 kg bleaching powder and 0.3 kg slaked lime with a little water, add to the balance, stir, stand 10 minutes, use the supernatant. |
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| 100 L of 0.3 % slaked lime | Paste 300 g slaked lime, add to the balance, stir, stand 10 minutes, use the supernatant. |
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| 100 L of 2.5 % chlorine dioxide | 250 g activator crystals plus 2.5 L Sanitech or Serichlor, stand 10 minutes; add to 97.5 L water with 500 g slaked lime. |
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| Appliance dipping | Immerse in 2 % bleaching powder in 0.3 % slaked lime for at least 10 minutes; a 6 × 3 ft tank filled to 2 ft holds about 1,008 L (1 cubic foot ≈ 28 L). Ten dips per batch of solution, then discard. Sun-dry until odour-free. |
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