Sterilizing cutting tools.

[DavidCampen]

In another thread we were discussing how to sterilize cutting tools to prevent the spread of virus. In that thread I said:

On further research I have to conclude that Physan is likely not capable of destroying most plant viruses.

I am going to have to rethink my tool (clippers) cleaning strategy. Hypochlorite is effective but it is corrosive to metal. Formaldehyde and glutaraldehyde are effective but they are nasty smelling and just generally nasty. Chlorine dioxide solutions are effective but are rapidly destroyed by sunlight. Alcohols are not very effective. I may have to start flaming my tools. I wonder if an alcohol lamp would be sufficient for flaming my clippers?


I have decided to move to flame sterilization, probably using a butane or propane torch.

One problem is the Fiskars brand shears that I am using have a lot of plastic - on the handle and in a lock slide.
I expect that I will likely eventually ruin that as I flame the blades. Japanese hand pruning shears are often available constructed only of metal. I would like some that have a spring that opens the blades. Does anyone have suggestion for a good but not too expensive brand?

[DavidCampen]

To answer my own question, I have decided to get Corona FS4350 and Corona FS4310 shears for evaluation.
Products : Corona Tools USA
They still have a plastic handle but it may be far enough from the blade to not be damaged and even if the plastic handle does melt it can be removed and not impare functionality.

For a torch I have decided to get an Iwatani chef's torch:
Amazon.com: Iwatani Torch Burner Professional #Cb-tc-pro: Kitchen & Dining

[Paul Mc]

I'll have to check these out! Thanks for posting the links!

[silken]

I have been told and read more than once that T.S.P. (the stuff to clean pain brushes etc.) is an excellent way to sterilize cutting tools. And supposedly it can be re-used as the effective part doesn't evaporate and I think the tools don't rust either. You mix it to a concentration that the water can't absorb any more of the granules. Can be found at most hardware and home improvement stores. I keep meaning to get some and this has just reminded me!

T.S.P. | Trisodium Phosphate Powder - 400 g | Home Depot Canada

[tucker85]

I've also been told that TSP works well for sterilizing tools. Chlorine works well also but it's rough on your clothing. When using a solution most people use two or more cutters so one can be sterilizing while using the other. I've been using a torch to sterilize my shears and I think it's the best solution for me. I haven't used the torch in the picture but it looks like a decent one. I don't know how long that little bottle will last though. It took me a few days to stop burning myself accidently by picking up the shears by the metal part. As far as the shears, I like any shears that are needle nosed. Shears with large blades don't work well around orchids.

[DavidCampen]

Here is a good study that was done at Ohio State as an undergraduate research project.
https://kb.osu.edu/dspace/bitstream/...NDA_THESIS.pdf

Findings were that hypochlorite (bleach) was by far the best but it causes corrosion of metal.

Two other oxidizing agents that worked well were ZeroTol and Virkon S. ZeroTol is the stabilized peracetic acid that Ray sells in RTU dilution. Virkon S is potassium peroxymonosulfate and is widely available in the U.S. Both ZeroTol and I think especially Virkon S will not cause the corrosion of metals like hypochlorite. All 3 of these - hypochlorite, ZeroTol and Virkon S have limited stability and probably need to be refreshed for each day of use. Also, with these and all other disinfectants, mechanical cleaning of the tool to remove dirt and sap prior to the disinfectant treatment is important.

After hypochlorite, the finding was that flaming was next best.

Surprisingly, a 20% solution of non-fat dried milk was found to be reasonably effective.

Quaternary ammonium compounds and TSP were found to be only slightly effective.

Virkon S:
http://www2.dupont.com/Emergency_Dis...ta%20Sheet.pdf

Virkon S Broad Spectrum Disinfectant | QC Supply

[Hedge]

I use a standard lighter to flame my blades, but thenI only have a small collection of plants. I'm surprised that the milk solution works. i always thought that milk was a prime feed for lots of nasties.

[bballr4567]

We use Cavicide in our Xray department to clean everything so I assumed its good to use to clean my shears.

Its cheapish and pretty much kills everything. Its also low alcohol so it doesnt dry out your hands like crazy either.

[DavidCampen]

I have to question if Cavicide is effective against the typical plant viruses. According to my very limited knowledge of virus taxonomy, viruses can be divided into 2 classes according to whether or not the virus has an envelope that encloses the virus capsid. Viruses that have this envelope are called encapsulated or enveloped or lipophilic viruses while viruses without this envelope are called non-encapsulated or non-enveloped or hydrophilic viruses. I believe that many of the plant viruses for which we are concerned are of the non-enveloped type.

The enveloped (lipophilic) viruses can be destroyed by surfactants such as quaternary ammonium compounds while the non-enveloped (hydrophilic) viruses remain mostly unaffected by these agents.
Viral envelope - Wikipedia, the free encyclopedia

While the Cavicide marketing literature does make claims that Cavicide will inactivate both lipophyllic and hydrophyllic viruses the Cavicide Technical Bulletin shows only tests demonstrating effectiveness against enveloped (lipophyllic) viruses.
http://www.metrex.com/cms-filesystem...lbulletins.pdf

The active agent of Cavicide appears to be a quaternary ammonium compound called Hyamine 1622. A paper from the USDA Animal Disease Laboratory shows Hyamine 1622 to be not effective against Foot and Mouth Virus which is a non-enveloped virus like many plant viruses.
http://www.ncbi.nlm.nih.gov/pmc/arti...00361-0062.pdf
Picornavirus - Wikipedia, the free encyclopedia

[Cym Ladye]

I have used a 10% solution of bleach and water for over 25 years and have a very low incidence of virus. When it does occur on testing, it inevitably comes from a plant brought in within the past year.

BUT--- I do not use shears! I use disposable, single edge razor blades which can be tossed (or baked in the oven at 325F for an hour), and cheap, serrated steak knives with plastic handles which can easily be soaked in the bleach solution. The only orchid use for my shears is to shorten new wooden stakes.

Cym Ladye