David Knox may not have been aware of the research at the time of his
conversation with you, but I can assure readers that the ability of bleach
(sodium hypochlorite) to kill AFB spores is not an urban legend.

For those who are interested, and have access to overseas beekeeping
journals, trial work showing that the substance is effective has been
reported in the New Zealand Beekeeper magazine (Goodwin, R.M., Haine, H.M.
1998. Sterilising beekeeping equipment infected with American foulbrood
disease spores.  New Zealand Beekeeper (5)9:13.)

The work was carried out by Dr. Mark Goodwin and his team at Ruakura
Agricultural Research Centre, Hamilton, New Zealand.  Mark is a
well-respected apiculture scientist who has carried out extensive research
on the causes and spread of AFB.

The following is a quote from a book Mark and I have written on AFB control
in New Zealand (Goodwin, R.M., Van Eaton, C. 1998. Elimination of American
Foulbrood Without the Use of Drugs:  A Practical Manual for Beekeepers.
National Beekeepers' Assn. of NZ, Napier, NZ.  78 pp.):

"Sodium hypochlorite is a commonly used sterilising agent, and is one of the
few disinfectants that is effective against AFB spores. Sodium hypochlorite
is the active ingredient in household bleach, and is present in such
products at about 3% concentration. Research conducted at Ruakura has shown
that concentrations of 0.5% sodium hypochlorite in water will kill all AFB
spores in 20 minutes.

Sodium hypochlorite is potentially useful to treat beekeeping equipment such
as plastic or metal feeders and plastic frames. It is important to note,
however, that sodium hypochlorite will only kill what it comes into contact
with, so any material to be sterilised must be very clean before treatment.

Care also needs to be taken with the types of materials being treated. Some
plastics, metals, and especially leather, can degrade when put into sodium
hypochlorite solutions. It is therefore worthwhile carrying out a small
trial run before doing any major sterilisation of equipment. The material is
not recommended as a disinfectant for gloves, hive tools or smokers, since
the 20 minute contact time is crucial to successful destruction of AFB
spores.

Sodium hypochlorite solutions must be kept in the dark, since the chemical
breaks down in sunlight. The solution should also not be kept for long
periods and must be disposed of safely after use.

Finally, a note of caution. The effects of bleach on clothing are
well-known, so protective clothing should be worn when using the material.
Eye protection is recommended. Some individuals also react adversely
(dizziness, fainting) to the fumes of sodium hypochlorite, so extreme care
is needed when using the material."

The important point to note is that sodium hypochlorite is only a surface
sterilant, and will not penetrate into wood, wax, propolis, etc.  In New
Zealand, we sterilise woodware recovered from AFB hives by dipping it in
paraffin heated to at least 160degC for at least 10 minutes.  Mark has also
done research to show this is effective.

Cliff Van Eaton

-----Original Message-----
From: William Morong <[log in to unmask]>
Date: Friday, 19 November 1999 3:50
Subject: Bleach and AFB spores


>In a recent post, Paul wrote concerning bleach "It sure will kill any
spores
>that are exposed though."   In checking my library and the archives I find
>many opinions that bleach will or will not so act, but no references to
>solid scientific evidence.   When I had AFB here, Mr David Knox of the USDA
>bee laboratory in Beltsville, MD wrote the following in an email to me:
>
>"You are correct, bleach will not kill Bacillus larvae spores, however
>anything you do to physically remove spores from your gloves, bee suit,
>hive tool, smoker, etc. will be of benefit.  Your protective clothes are
>perfectly safe to use after washing with a good detergent."
>
>I would not be surprised if bleach were deadly to the more vulnerable
active
>bacterial form of the pathogen, but does this form ever exist in the sure
>absence of spores.  If Paul or anyone else has sound scientific evidence
>that bleach is deadly to AFB spores, I would much appreciate further
>education on this, and the knowledge itself would be delightful.  If not,
is
>not AFB too dangerous to become the subject of legends.
>
>Bill Morong
>