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Healthy Farms - Healthy Agriculture

Disinfection in On-Farm Biosecurity llama photo by Krista Cheney, link to home page

General Farm Biosecurity Practices—
Disinfection in On-Farm Biosecurity

Choosing a disinfectant is a complex process. There is no one best product for all situations. You must consider the disease risks about which you are concerned, the type of surface you wish to disinfect, the conditions under which the disinfectant will be used, and then select a disinfectant that best suits your needs. When using a disinfectant, it is important to consider the following points:

  1. Most disinfectants won't work if the surface to be disinfected isn't clean before applying the disinfectant.
    • Organic materials such as soil, plant debris (e.g., straw), milk, blood, pus, and manure inactivate some disinfectants or protect germs from the disinfectant's active ingredients.
    • Chlorine-based products are especially subject to this problem.
    • Wash boots, equipment, or housing areas first with water and detergent.
    • Use steam and high-pressure washers to clean porous surfaces.
  2. Disinfectants vary considerably in their activity against the assorted germs—bacteria, viruses, fungi, and protozoa—associated with livestock.
    • Plain vinegar (4% acetic acid) will readily kill the Foot and Mouth Disease virus, but is not effective against Mycobacterium avium paratuberculosis (MAP), the cause of Johne's disease.
    • Most commonly used disinfectants are not active against bacterial spores, which are the environmentally hardy life form of the germs that cause tetanus, blackleg, botulism, and anthrax.
    • The spectrum of activity of various classes of disinfectants is shown in this chart of general use disinfectants.
  3. It is important to select a disinfectant that will be active across a wide spectrum of germs under the conditions in which it will usually be used.
    • Check the pH (acidity or alkalinity) of your water. Hard water can reduce or destroy the activity of some disinfectants.
    • Use the recommended water temperature for dilution or maintain at the recommended ambient temperature to ensure optimal activity.
    • Know the shelf life of the chemical or the age of the mixture. Some lose activity quickly after being diluted.
    • Record when you mix each solution of disinfectant and refresh regularly. A solution that has been contaminated by organic material like manure, will have decreased effectiveness.
    • Wear protective equipment if indicated. Some chemicals, especially at full strength, may be toxic or cause damage to skin, clothing, or environmental surfaces.
  4. Disinfectants must have sufficient contact time with the surfaces to allow them to kill the germs. The required contact time varies with the product and the germ. In any case, a quick splash of a dirty boot in a footbath is not likely to accomplish anything except to give a false sense of security.
    • Allow sufficient contact time for the disinfectant to do its job.
    • Follow label directions closely and do not mix different classes of disinfectants.
  5. Disinfectants are not to be applied to animals directly, unless labeled for such use.
    • Consult the label to make sure there are no warnings against using them around feeders and in animal quarters.
    • Rinse disinfectants off after the appropriate amount of contact time if animals will have contact with the disinfected surfaces.
  6. Disinfectants vary in their toxicity to the environment.
    • Follow directions for disposal to prevent environmental contamination.
    • Antimicrobial agents used on the environment are regulated as pesticides by the Environmental Protection Agency (EPA).

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Last modified October 06 2010 09:16 PM

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