Soaps and Detergents — Use soaps and detergents for the cleaning step, which is 

 the most important one in cleaning and disinfecting. Proper cleaning will remove 

 up to 99 percent of infectious material and render the surface visibly clean. These 

 agents serve to saponify lipids present in the cell walls of bacteria and in the envelope 

 of many viruses, effectively inactivating them. Soaps and detergents also peptonize 

 proteins, which helps to remove biofilms composed of animal exudates, secretions, 

 and excretions. Disinfection is useless without proper cleaning beforehand; you 

 cannot disinfect soil (manure, dirt, secretions, excretions). 



Phenols — Phenols are protoplasmic poisons that can readily be absorbed through 

 the skin. In concentrated solution, they cause severe burns and are fatal if swallowed. 

 Phenols are effective against boih gram-positive and gram-negative bacteria and 

 most of the enveloped viruses. One of the substituted phenols, 2-phenylphenol, 

 is particularly effective against Mycobacterium species, w iiich arc normally quite 

 refractory to disinfectants. Note that ncmcnveloped viruses, and bacterial spores at 

 ambient temperature, are very resistant to phenols. 



Acids — The hydrogen ion (H+) is bacteriostatic in the pH range of 3 to 6 

 and bactericidal when the pH drops below 3. The following acids can be used 

 as disinfectants: 



1. Carbolic acid: This is a water solution ot phenol and is mentioned in 9 CFR 

 part 71.10(a)(2) as a permitted disinfectant. The requirements of 9 CFR part 

 71.10(a)(2) state that liquefied phenol (L'.S. I'harmacopoeia [U.S.P] strength 87 

 percent phenol) should be in the proportion of at least 6 tluid ounces to 1 gallon 

 of water. 



2. Cresylic acid: This is a combined fraction of cresols and xylenols and is 

 also mentioned in 9 CFR part 71.10(a)(1) as a permitted disinfectant. The 

 requirements of 9 CFR part 71.10(a)(1) state that cresylic disinfectant should be 

 in the proportion of at least 4 fluid ounces to 1 gallon of water. As a disinfectant, 

 cresylic acid is more effective than phenol. 



3. Mineral acids: These can be used for disinfectants, but they are highly corrosive. 

 Hydrochloric acid (FlCl) is sporicidal and has been used at a concentration of 2.5 

 percent as a soak to disinfect hides potentially contaminated with anthrax spores. 

 As an example that all disinfectant materials are not uniformly effective, it should 

 be noted that sulfuric acid (H,SO^) is not sporicidal. 



4. Organic acids: These are effective disinfectants and are less corrosive than 

 mineral acids. Citric acid is readily available in the food industr\ and has been 

 used as an additive to detergents to disinfect for the virus that causes foot-and- 

 mouth disease. Acetic acid (5 percent white vinegar) is being routinely used to 

 wipe down horses coming into the United States from other countries in an 

 attempt to ensure that they are not carrying the foot-and-mouth virus on 

 their coat. 



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