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Posted

I'm going to make a 100 liter solution to desinfect various tools used in Shiitake production so it's important the solution kills mold and mold spores.

I've been looking into various methods and chemicals. At first I thought about going with H2O2 since it's safe and does not generate harmful by-products. Since I do not have peroxide stronger than 3% readly available I discarded this route.

I thought about a solution of calcium hypochlorite taking the PH below 7 but since that would probably be quite dangerous since I'm not sure about the concentrations / ph levels used to generate minimum ammounts of chlorine gas. I surely don't want to be dealing with the release of chlorine gas if I can avoid it.

I looked into chlorine dioxide and althought extremely effective it's also very toxic and even has explosive properties. I discaded it immediately.

Lastly I saw that my supermarket carries Trichloroisocyanuric acid (pool shock) at 96%.

I was reading some info here and it's dangerous to mix with small ammounts of water and also I need to be careful about the PH.

These are the recommended concentrations for each use:

  1. swimming pool disinfection: calculate the usage according to 2-3g/m3; take effect for 30-60 minutes.
  2. Public places and ground disinfection: use 1500-3000-fold diluted water solution for spraying and wiping for 30 minutes. Infectious disease epidemic area, use 150-200-fold aqueous diluted water solution for spray disinfection.
  3. disinfection of white clothing and blankets: apply 2000-3000 fold diluted solution for clean items; soak for 10 minutes; for seriously polluted items, diluted 500 times, soak for 20 minutes.
  4. disinfection of bathroom and toilet scrub; use 300-fold diluted solution for reaction of 30 minutes.
  5. sterilization of non-metallic medical equipment: use 500-1000 times diluted solution for soak of 30 minutes; disinfection of apparatus with pus and blood; apply 100-fold diluted water solution for reaction of 30 minutes.
  6. disinfection of non-metallic tableware: use 500-1000 times diluted water solution for reaction of 30 minutes.

My questios are:

1. How many grams should I had to 100 liters of water for sterilization / desinfection of equipement? (I'm looking into a strong solution but also safe to use)

[EDIT] I found this patent that states

with a sterilizing solution of a compound having an active-chlorine concentration of from 500 to 20,000 mg/l and being selected from the group consisting of sodium hypochlorite, calcium hypochlorite, chlorinated trisodium phosphate, chlorine dioxide, sodium p-toluenesulfochloroamide, p-toluene-sulfonsulfochloroamide, N-chlorosuccinimide, 1, 3-dichloro-5, 5-dimethylhydantoin, trichlororoisocyanuric acid, salts of trichloroisocyanuric acid, trichloromelamine and dichloroglycoluril, the pH of said sterilizing solution being from 8 to 10, and treating the thus sterilized article with an aqueous solution of hydrogen peroxide at a temperature below 90° C to deactivate any remaining active chlorine, said solution of hydrogen peroxide having a concentration of lower than 30%.

Also fromhere

using a solution of concentration of 200-400 mg/kg for environmental disinfection and utensils disinfection.

Since my solution will be made with water I would assume mg/kg = mg/l

So for a 100 liter solution I would need to dissolve 20-40 grams, correct me if I'm wrong.

2. What would be the recommended PH value for maximum effectiveness but also safe to use?

On a side note the desinfection will be carried at a open area using adequate PPE.

[edit: I would also need to know an approximate time the equipement needs to be submerged and how long the solution would be effective]

Posted

This mushroom seed spawn/culture supplier uses 10% bleach solution (sodium hypochlorite)  to clean surfaces and scrub the air. They use calcium hydroxide to sterilize substrates. Obviously, make sure you've got the correct PPE (personal protection equipment) for sterilizing (misting) the air.

http://www.funguys.co.za/mushroom-cultivation-tips/growing-mushrooms/cold-water-sterilize-with-calcium-hydroxide/

Posted
39 minutes ago, StringJunky said:

This mushroom seed spawn/culture supplier uses 10% bleach solution (sodium hypochlorite)  to clean surfaces and scrub the air. They use calcium hydroxide to sterilize substrates. Obviously, make sure you've got the correct PPE (personal protection equipment) for sterilizing (misting) the air.

http://www.funguys.co.za/mushroom-cultivation-tips/growing-mushrooms/cold-water-sterilize-with-calcium-hydroxide/

 

According to my research bleach does not kill fungal spores on non-pourous surfaces unless acidified, which would release chlorine gas (quite dangerous). If I had unlimited supply I would go with H202 but it's not really a cheap solution.  I will look into calcium hidroxide for substrate sterilization. 

 

Thanks for your input StringJunky.

 

 

Posted
1 hour ago, John Cuthber said:

If you use tools with non-porous surfaces- glass, metal, plastic- then they are much easier to clean and can be sterilised with ordinary bleach.

I know so, the problem is I already have quite a few non-porous surfaces that I need to desinfect or otherwise discard them.  Would you think that a solution of  Trichloroisocyanuric acid at the above forementioned concentrations would get rid of any mould spores even on mon porous surfaces?

Posted (edited)
50 minutes ago, giovannimclaughlin said:

I know so, the problem is I already have quite a few non-porous surfaces that I need to desinfect or otherwise discard them.  Would you think that a solution of  Trichloroisocyanuric acid at the above forementioned concentrations would get rid of any mould spores even on mon porous surfaces?

Your non-porous surfaces are the easiest to clean, which bleach should be perfectly adequate. I'm not sure if English is your first language but 'non-porous' means smooth and won't absorb anything, including spores. Even on porous surfaces, bleach should be fine as long as you dry them out properly. Plain, diluted bleach will just evaporate.

Edited by StringJunky
Posted
26 minutes ago, StringJunky said:

Your non-porous surfaces are the easiest to clean, which bleach should be perfectly adequate. I'm not sure if English is your first language but 'non-porous' means smooth and won't absorb anything, including spores. Even on porous surfaces, bleach should be fine as long as you dry them out properly. Plain, diluted bleach will just evaporate.

Yes, but it might not actually do the job.

 

3 hours ago, giovannimclaughlin said:

According to my research bleach does not kill fungal spores on non-pourous surfaces

It's not a linguistic problem.

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