Chlorocresols
This type of modern phenol is often used as a terminal disinfectant in house cleaning. These disinfectants have to be used at relatively high concentrations of 2-4% against viruses but are extremely effective against bacteria at 0.5% even in the presence of high levels of organic matter (test method EN 14349). (Some farms use a chlorocresol disinfectant in the foot dip of chick & pullet housing to prevent field strains of coccidial oocyst being walked in and interfering with coccidiosis vaccination programmes.)
Glutaraldehyde
Glutaraldehyde + Formaldehyde disinfectants
These are the least sensitive to the presence of organic matter, they are also ideal for use in foot dips, providing the outside temperature stays above 4-5ºC.
Glutaraldehyde + quaternary ammonium salts
Combination products of “gluts” and “quats” are disinfectants quite common. Although improving performance at lower temperatures, efficacy against nonenveloped viruses is sacrificed. There are many glut/quat approved disinfectants approved under test criteria ALL would require a foot dip concentration of between 2–6% to be effective against ALL viruses, bacteria and fungi.
Oxidising disinfectants
This group of disinfectants are sensitive to the presence of organic matter and generally have to be used at a concentration of 1–2% although there are some well-known products in this class which should be used between 3–5% to ensure complete disinfection. When using oxidising disinfectants, the operator should make sure that the solution is changed frequently to avoid loss of efficacy. Oxidising disinfectants are excellent in cold weather, when temperatures are near zero, and make can be useful as an alternative to glutaraldehydes and chlorocresols during cold winters.
Iodophores
These are not as sensitive to low temperatures. They have a similar tolerance to organic matter as the glutaraldehyde plus quaternary ammonium salt type disinfectants. Their chemical basis is iodine which tends to discolour and stain surfaces and materials with which it comes into contact with. In general, a 2% solution, changed frequently, should provide a useful concentration for a footbath, colour is not necessarily a good guide as to its efficacy.
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