We have been prompted to write this article to clear up some misunderstandings that growers may have on the subject of disinfection especially with our own product SporeKill which has a unique product mechanism. 

Many commercial disinfectants in the mushroom industry contain synthetic chemical products called phenols and chlorophenols. These are effective as quick kill bactericides and fungicides, but there are significant downsides including long term toxic effects via skin OR inhalation on users. This is well documented on the health and data sheets for most active ingredients that these commercial products use. The dangerous nature of these very useful chemicals should not be underestimated and demands that great care is exercised in their use.

It is not generally appreciated that there are natural occurring non-toxic but very powerful antifungal substances existing in animals green plants and fungi. These anti-pathogenic substances have developed over many millions of years as protective mechanisms. They usually work by preventing the development of and preventing proliferation of bacteria or moulds. Obviously if you suspend the life process of a spore within these natural products it is soon extinguished permanently.

We have been utilising technology with naturally occurring Carboxylic acid salts as safe and effective compost supplements for the last fifteen years during which time no cases of compost mould development (as a result of supplementation) have occurred. In fact we can suppress low-level pathogen contamination in borderline compost.

The same basic technology has been utilised to develop SporeKill ™. The product has very powerful wetting and penetrating properties to ensure that any residual soiling or porous surfaces in the growing room are fully saturated with the product and this puts the mould or mould spore into suspended animation. As evaporation occurs the product becomes a relatively thick film over any pathogenic organisms, which are not able to function and so become non-viable and are soon destroyed. 
The standard mushroom farm clean-up technique is to spray out in the afternoon followed by fill next morning. This is a well-proven and absolutely safe method of disease free growing practice. From the clean-up teams point of view the product is absolutely non-toxic and non-carcinogenic and causes no environmental problems.

Some tips for maximising efficacy of SporeKill ™ are given below.

The physical nature of the soap component (sticking/trapping effect) is equally important as the chemical effect with relation to spores so our product is designed not to be washed down after application. We have Soil Association dispensation for the non wash down methodology.

Fogging
SporeKill ™ works well in this situation with electric fogging machines or compressed air misting systems, the finer the particle size the better! Fogging should precede any other emptying activity as it is the fine soap particles that trap spores and dust and prevents any further movement. Use at label rate.

Washing down walls and floors
SporeKill  ™works well on general washing down around the farm. The soap component is insoluble on calcareous surfaces thus giving protection for a long period. It importantly fills the tiny surface voids in concrete preventing recontamination. Use at label rate.

Footdips
SporeKill  ™ is suitable for foot dips, the soap component is thick at 2%, so any spores around will be stuck to the soap matrix on boots and trapped, as they dry the chemical action will destroy the spore.

Nets
SporeKill   ™ is fine here because they are soaked for at least 8 hours, the alkalinity and antifungal exposure for this period will be effective as spores will be destroyed. Always use fresh made up solution for each time you dip. SporeKill  ™is permissable to come into contact with compost after cleaning being a PPP whereas phenols as biocides are not (see EU borderline document)

Machinery washdown
SporeKill  ™is suitable for this as long as surfaces get a minimum of 8 hours to dry. Machinery must be under cover, its no good if its washed off immediately!

End of Crop
Flooding the surface of the casing with SporeKill ™will help reduce aerial spores by its sticky physical effect prior to emptying. If left for 8-12 hours its fungistatic effect as it dries will enhance this further.

Over five years of on farm evaluation there has been no sign that this naturally based product is any less effective than the synthetic Phenolic chemical alternative. In our own test unit (with no cook out facilities) we have not suffered from any serious outbreak of disease during this time. This is borne also out by all our customers in a number of countries who use our product consistently.

It should be noted that certain standard biological assay methods have been shown to show SporeKill ™ in an unfavourable light when compared with Phenolic or Chloro-phenolic industrial disinfectants. These tests measure a speed of toxicity but not a true measure of practical mushroom farm hygiene. The effectiveness of SporeKill ™ is also cumulative as active residues penetrate and protect inaccessible places.
Finally, many customers ask us why we have it registered as a Plant Protection Product (PPP). The answer simply is that it permits the use during the cropping process. There is an EU borderline document that clearly cites (with mushrooms) that PPP products must be used if they come into direct or indirect contact with cropping surfaces. More importantly though we currently have nothing to use to protect the mushroom crop during its 5-8 week cycle. It is for this reason that we are going through the costly process of product registration. The methodology of control during cropping will be by fogging, for which our product is safe to both user and crop when applied at the correct stage. We have been carrying out residue work on mushrooms themselves with these treatments (in association with Kinsealy) and we will have news on this in the near future.

  Watch this space... 
For further information please contact Stuart Whitehall directly on +44 07721 639959 or Michael Costello on +353 86 856 9675.