In days of yore when petrol was half a crown a gallon and kerosene was two shillings, growers did a very thorough job of cooking out.

Relatively cheap steam was injected into the cook out room until the exhausted beds reached 65C.  This temperature was then maintained for at least twelve hours.  This long time span could easily be afforded in terms of comparatively good mushroom prices and cheap heating oil.  This temperature is capable of killing mushroom pathogens such as Verticillium, Mycogne, Cobweb and Trichoderma.  The first three moulds are the most vulnerable to the steam being mostly in the casing layer.  Trichoderma on the other hand is distributed deep in the compost.  Dry patches in the compost will be very good insulators and will not kill temperature for many hours, even so many growers try to raise the bed temperature to 65C and then turn off the steam, in the hope that all parts of the beds are equally penetrated.

An additional safety technique is to soak the beds before cook out with Sporekill solution. The SporeKill is designed to form a sticky antifungal film which will entrap spores and will prevent spores flying around the farm  on emptying the room. This technique is particularly aimed at the moulds on the casing surface. The non-toxic biodegradable nature of the Sporekill allows the treated compost to be used directly as agricultural soil conditioner and fertilizer having no dangerous soil residues and having an enhanced potassium status.

Further information can be found at www.nutrigain.com/blog or by contacting Stuart Whitehall on +44 7721 639959.