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What is cold sterilization and why is it the way of the future for mushroom farmers?

Written by Dr. John Holliday on April 5, 2018

Cold Sterilization is the big breakthrough the mushroom industry has been waiting for. In fact, it is the paradigm shift that mushroom farmers have been dreaming of for years! It is changing the whole concept of growing mushrooms, and cold sterilization is raising profits to levels unheard of even just a few years ago. So what exactly is this revolutionary breakthrough called Cold Sterilization?


Cold Sterilization is the use of common and cheap chemicals to sterilize the substrate before inoculation with mushroom spawn. Instead of using steam heat for sterilizing, we can simply soak the substrate in common, non-toxic chemicals. An example would be to soak straw in Hydrated Lime or powdered swimming pool chlorine. The rapid shift in pH or the oxidation from the chlorine kills off the vast majority of microorganisms and the higher pH does not affect the growth of many species of mushrooms, such as the Oyster mushrooms. When chlorine is used, the chlorine is neutralized before the substrate is used. Low magnesium hydrated lime is the cheapest and highly efficient for many species, especially all the varieties of Oyster mushrooms. Other types of mushrooms may not grow well in the high pH from lime, so then we use other chemicals, such as soap, or swimming pool chlorine, or a few others depending on the species. When chlorine is used, it results in true sterility, so almost any mushroom can be grown in that, as long as the chlorine is neutralized first. And all of these methods are OK for USDA Certified Organic production!


The concept is to soak the substrate, or alternatively we can set up a shower method, where the substrate is both hydrated and sterilized at the same time. This cold sterilization method is a proprietary system developed by John Holliday, the Senior Consultant here at Mushroom Consulting LLC. The first system was set up in Egypt, and another quickly followed in Israel. Dr. John first published the technical papers in peer reviewed scientific journals on this system back in 2004, and has been perfecting it over the last 15 years since then. There are now more than 100 cold system farms in operation around the world, and the results are phenomenal. 


No other system for cultivating mushrooms can be built as cheaply, and no other system has such consistently high yields as the cold sterilization system. It is not at all uncommon to see farms maintaining 175% BE, and doing this while using NO STEAM AT ALL! And this is done at a fraction of the cost of building similar capacity hot steam-system farms. Usually about 1/10 of the cost of the same capacity steam sterilize farm.


In the traditional model of growing mushrooms, the substrate is sterilized in large autoclaves or retorts using pressurized steam. This requires some very expensive equipment, including at a minimum, a steam boiler and a large autoclave. These two items alone can cost more than a quarter million dollars for a commercial size farm, one sized to produce a yield of 10,000 – 15,000 pounds of mushrooms per month. Yet rather than the $3 – $10 million cost for building the traditional farm, setting up a cold system commercial farm for this same yield only costs between $35,000 and $250,000 TOTAL COST! In short, for any size farm operation, a cold system farm is at least 90% cheaper than the same size farm using steam sterilization. And Dr. John has now perfected the cold system to work with just about any species. 

In fact, he also produces specifically optimized pelleted substrate that has the specific nutrient profile required to optimally produce whatever species you want to grow. The pelleted substrate is pre-sterilized, and optimized as far as the pH and nutrient profile for whatever species is desired. If you would like to learn more about this type of mushroom cultivation, please click on the Free Case Study button for more information.



Dr. John Holliday

Dr. John helps people start and grow successful mushroom cultivation businesses. He is an expert at growing all species of exotic mushrooms by integrating modern biotech methods and making things super simple to understand.


If you’re interested in starting your own mushroom business or scaling up and increasing your profits then definitely reach out and request a free strategy session today.