HERD HEALTH
PIH80
pork industry handbook
PURDUE UNIVERSITY COOPERATIVE EXTENSION SERVICE • WEST LAFAYETTE, INDIANA
Selection and Use of Disinfectants in Disease Prevention
Authors
H. Neil Becker, Melrose, Florida
George W. Meyerholz, USDA, Washington, D.C.
Jack M. Gaskin, University of Florida
Reviewers
Glenn and Miranda Elliott, Galivants Ferry, South Carolina
Duane Miksch, University of Kentucky
John Thomson, South Dakota State University
Kurt Wohlgemuth, North Dakota State University
Cleaning and disinfecting are very important in controlling the accumulation and spread of disease-causing microorganisms. It also improves air quality and reduces dust. This is especially true in modem swine buildings where continuous use and high concentrations of animals may result in a condition referred to as “disease buildup.” The all-in, all-out management program is recommended to facilitate the cleaning process and to improve pig performance.

As disease-producing bacteria, viruses, fungi, and parasite eggs accumulate in the environment, disease problems can be transmitted to each successive group of animals raised. Thorough cleaning and disinfecting often provides the only successful solution to breaking the disease cycle and controlling the problem.

Disinfection can be improved when the area is thoroughly cleaned. Organic matter such as dirt and manure can protect microorganisms and inactivate certain disinfectants. Manure removal followed by a simple scrubbing, a high velocity stream of water, or a steam generator can do an excellent cleaning job. Detergent solutions hasten dirt and manure removal by increasing the wetting speed and breaking organic matter into small particles that easily wash away. A siphoning system or propor-tioner can be utilized to combine a detergent or a detergent-disinfectant with the cleaning process. A high pressure stream of water or spray (200-1000 psi) can be used to remove manure and debris. Portable steam generators, “steam jennies,” are also used for cleaning dirty surfaces. The nozzle should be held not more than 6-8 in. from the surface to have much value in killing organisms. The steam cleaning-detergent process works effectively on wood, metal, concrete and especially on slotted and wire floors. Many disinfectants and detergents work better at warm temperatures of the steam generator. Effective cleaning removes more than 95% of the contamination and permits disinfectants to more easily penetrate and kill organisms.

Choosing a Disinfectant
Many factors must be weighed before choosing a proper disinfectant for a particular job. A germicide intended for the
disinfection of a building should work well in the presence of organic matter, be compatible with soaps or detergents, be harmless to building materials, and be relatively non-toxic. A disinfectant suitable for decontaminating a building might be too toxic for use in sanitizing feed and water utensils. Select the disinfectant to fit the job.

Chemical agents have different mechanisms of action and spectra of activity. Warmer temperatures with some disinfectants, such as those containing chlorine or iodine, drive off the active ingredient from the solution. Some disinfectants are influenced by an acid or alkaline pH and/or hardness of the water. Characteristics and uses of common disinfectants can be evaluated using Table 1.

Commonly Available Disinfectants
Saponated solution of cresol is almost insoluble, especially in hard water. Compounds of cresol with soap (saponated) such as Lysol® are normally used to increase solubility and are applied in a 2-4% solution; a dilution of 4 oz. of cresol per gal. of water is recommended. Hot solutions are more effective. Saponated solution of cresol is an effective disinfectant to use in the presence of organic matter and is suitable for disinfecting animal quarters, vehicles and premises. These compounds can also penetrate wooden materials. Cresol has a strong and persistent odor to consider when using in farrowing houses or other tightly enclosed buildings.

Synthetic phenols such as orthophenol are available. They have a wide range of antimicrobial activity and are relatively good in the presence of organic material. They usually have no objectionable odor. Some are fortified with synthetic detergents for one-step cleaning and disinfecting. They are sold under various trade names (see Table 1).

Free Iodines: Tincture of iodine (2% iodine in alcohol) and strong tincture of iodine (7%) have been used as antiseptics and disinfectants; but because of their staining, corrosive and skin irritant properties, organic or “tamed” iodophor compounds are commonly used. Tincture of iodine could be used on skin prior to, or after, minor surgical procedures such as castration. As
Cooperative Extension work in Agriculture and Home Economics, state of Indiana, Purdue University and U. S. Department of Agriculture cooperating. H. A. Wadsworth, Director, West Lafayette, IN. Issued in furtherance of the acts of May 8 and June 30, 1914. The Purdue University Cooperative Extension Service is an affirmative action/equal opportunity institution.