Common Disinfectants and their Usage
By, Dr. Assan Kasim, Thirunelveli, TN, India
- Bleaching powder (Chloride of lime)
It can be used for disinfection of animal houses when a contagious disease has occurred and for sterilization of water supplies.
- It should not be used in milking barns as its strong odour may taint milk.
- Concentration required is not less than 30 per cent available chlorine.
Mode of application is dusting.
- Bleaching powder must be stored in airtight bins as damp surroundings, exposure light and air causes it decompose rapidly.
Boric acid
- It can be used as an udder wash.
It is a week antiseptic and is likely to harm nervous system if absorbed into body in large quantities.
- It is used as wash for eyes and other sensitive parts of body.
Concentration required is 6 per cent solution.
- Mode of application is splashing.
Nowadays antibiotic solutions are replacing boric acid as eyewash solution.
Caustic soda (Sodium hydroxide)
- For general use in farm buildings and animal houses, caustic soda is a very effective disinfectant as it is an excellent cleaning agent as well as a powerful germicide.
2.It is highly destructive to virus of foot and mouth disease, hog cholera etc.
It is not effective against tuberculosis and johne’s disease organisms.
- Concentration required is 2 per cent solution for general use and 5 percent solution against spores of anthrax and black quarter.
- Mode of application is splashing.
Rubber gloves, goggles and protective clothing should always be worn when caustic soda solution is being used as it burns skin and damages fabrics.
Cresols
1.The cresols are only slightly soluble in water and are therefore generally emulsified with soap.
2.Effective against a wide range of organisms including acid fast tuberculosis and Johne’s disease bacteria but not effective against viruses and spores.
3.Good for disinfecting floors, walls, equipment etc. but not in milking barns because of its phenolic odour.
4.Concentration required is 2-3 per cent.
5.Mode of application is splashing.
6.Use only soft water for preparing solutions, hard water precipitates soap.
Lysol is a solution of cresol with soap.
Lime (Calcium Oxide, quick lime)
- It is a deodorant as well as a disinfectant.
- It can be used for sprinkling on manure and animal discharges, on floors or as a whitewash or milk of lime (also known as slacked lime).
- Mode of application is sprinkling, scrubbing or sometimes dusting.
4.Always use freshly prepared lime only.
Phenol (Carbolic acid)
- Effective against several types of bacteria; not so effective on spores and viruses.
2.Its disinfectant value is not reduced by the presence of organic matter but oil or alcohol does so.
- It is very toxic, corrosive and irritant.
Concentration required is 1-2 per cent.
4.Mode of application is splashing.
Great care should be taken in using phenol to protect eyes, skin and clothing.
Quaternary Ammonium Compounds (QAC)
- These are cationic detergents.
They have no effect on spores and viruses.
They can be used to disinfect dairy utensils, udders, milkers’ hands and towels for wiping udders.
Cetrimide, a white powder is an example for QAC.
- Concentration requires is 0.1 per cent solution (0.5 per cent cream for applying on teats and hands to prevent mastitis.
- Mode of application is wiping of udder with clothes wetted in 0.1 per cent solution; washing of milkers’ hands.
Utensils should be scrubbed with boiling water before rinsing with QAC.
Soap
- Soap is an anionic detergent.
It is a very week germicide.
But its great usefulness in cleaning various surfaces including skin.
- It can be used preparatory to the application of a disinfectant.
Mode of application is scrubbing.
It should preferably be used only as surface-sanitizing agent.
Sodium hypochlorite
- It is a chlorine compound.
It is an excellent disinfectant but is not effective against T.B bacteria and its effectiveness is reduced by the presence of organic matter.
2.Concentration required is 200 parts per mil
