Dirt, or soil, is a rich and ever-present source of bacterial and fungal growth.

Soil from the earth is composed of an inorganic part – containing oxygen, magnesium, sodium, iron, quartz, silicon dioxides, and many other minerals depending on the local geology; and an organic part – of amino acids, proteins, sulphides, nitrogen and phosphorus oxides, and other hydrocarbons. ‘Soiling’ from poultry droppings and waste is of course primarily organic.

When still present, dirt presents a real barrier to effective disinfection because most disinfectants are consumed and hence inactivated by the soil. This is why the industrial standard is of course first to clean prior to disinfection.

Despite the best efforts of practitioners however the cleaning process is not always 100% successful. Cracks in cement and joints in steel harbour pernicious dirt.

Poultry growing barns in some countries have floors of beaten-earth only, and not everywhere has access to high pressure cleaning apparatus. In a study conducted it was shown that up to 20% of soil still remains after the cleaning step.

The message is clear: a good disinfectant should be as stable as possible in the presence of soil. Around the world, regulatory standards are catching up to this fact by the increasing importance of efficacy results in the presence of organic soil.

Typically, hypochlorites, peroxides / peroxygen formulations, and formaldehyde are highly affected by soil. The fast-reacting molecules of these biocides are quickly inactivated when they oxidise or react with organic matter; and they are less likely to penetrate the soil far enough to reach and act on pathogens.

Phenolic types and the universal disinfectant Halamid® are less affected. Being more chemically stable, they migrate further through a layer of soil, still active and able to destroy pathogens.

For example, studies demonstrate that 60% of Halamid® still remains active in soiled water after 24 hours whereas a Peroxygen/Persulfate formulation decreases to 10% activity and Hypochlorite is fully consumed.

Similarly, testing of Halamid® efficacy against various pathogens show hardly any difference in dosage required for the same killing effect at low level and high level soiling; whereas most disinfectants need to increase the dosage considerably to pass the test.

Arno Schut , Halamid® Technical Manager commented on the problem: “It’s true that some disinfectants are much more stable than others and won’t hold up so well in dirty conditions.

"Of course the ideal advice is clean thoroughly first but I’ve seen a lot of places where practise doesn’t live up to that theory! Phenolics and Halamid® both work well in these conditions. Halamid® has the added benefit of a safer profile for users.”

Further information on Halamid® can be obtained from www.axcentive.com, by emailing [email protected] or by calling the Axcentive sales office on +33 442 694 090.