Mold

Sue Gatenby <sueg [at] phm__gov__au> writes

>I am trying to plan a mould reduction programme for a large storage
>area with mould outbreak. I want to consider the use of UV light
>(200-300nm) combined with Bactigas treatment (tea tree oil active
>component) to reduce the air sopra and surface mould while a clean
>up is undertaken and environmental conditions are up-graded and
>improved.

Olivia Primanis forwarded some moldy correspondence re your request
for comments re airspora control while cleaning up a moldy area and
improving the environmental conditions.

The use of both UV and the tea oil are treatments to kill or prevent
germination of the conidia.  Unfortunately this is only half the
problem.  Even if killed the fungal structures; conidia or
beta-glucans in hyphal fragments are antigenic or mycotoxic.  These
characteristics are not altered by the treatments.  The conidia may
be dead but if antigenic they are still a health hazard.

UV is used in mycological research to sterilize fume hoods or small
rooms used for culture inoculation.  These are small areas and the
UV can be used for long periods of time( when the unit is not in
use) in the small areas, and is mainly to sterilize surfaces.  It is
used industrially, I believe, on some food products but is
concentrated on the surface of small packages.  Surfaces are
sterilized but not the air.  The UV wave length and duration of
treatment for air would have to be tested and it could only be
accomplished if air was circulated into the UV unit.

The air to become free of conidia needs to be filtered, but air
movement may cause unwanted increase in airspora. The unnatural use
of the natural product tea tree oil can only be considered if it is
shown not to present a health hazard.  These volatile plant oils are
terpenes which can be very active chemicals and present health
hazards at certain concentrations.  There is little research on this
problem but what there is shows clearly that they can be
concentrated in fats.  When we breath them they could eventually be
concentrate in body fat and myelin sheaths of nerve tissue.

The action of pyrethrin, the natural product, acts on insects by
doing the latter.  The treatments using volatile oils all allow the
volatile chemical to go into the air we breath.  An increase in
neurological disorders have been shown to be related to increase use
of such products in household.  There certainly is a message in
that.

Sue, if I was involved in your task of clean up, the first thing I
would do is to monitor the conidia load by using a method which give
you information on the number of viable colony forming units
(CFU/vol air) and the total of conidia and hyphal fragments.  The
total conidia and hyphal structures count is done by microscopy and
can be determined in a day, culturing takes a long time.  The CFU/
vol. of air will tell you if there are viable conidia which the
"culture technique used" can grow-nothing more.  The beta-glucans is
in the hyphal fragments as well as conidia.

The results of this monitoring would be the standard on which you
can determine if cleaning up has lowered the airborne fungal
structures.  At different stages during the clean up you can monitor
the air to see if a reduction has occurred.  Cleaning surfaces will
pick up the fungal structures that have settled.  These surfaces
should also be monitored.  During the cleaning process cleaned
surfaces can easily become contaminated again.  Monitoring the
surfaces, using scotch tape surface sampling of total conidia and
fragments can be done by microscopy.

I would also make sure that I follow aseptic techniques to prevent
cross contamination etc.  The details are given in my article in
JAIC.  I would assume that there is a health hazard and take all
precautions, re garments and masks.

If your monitoring shows that there is not a significant reduction
then I would look at other methods, probably some air circulation
with Hepa filtering.  This does not have to be expensive, even a
vacuum cleaner with a hepa filter attached by duct tape to the
exhaust can function as a air filter.

I am recommending at my fungal facts workshops that an initial
monitoring of airspora should be done as a standard to air quality
in museums.  This could be done four time a year to correspond with
the seasons and used as an important  reference if a fungal
infestation occurs. Usually the fungal infestation occurs and there
is no reference.

Well I have said a lot, but I think you should proceed with your
clean up and monitor and if you think you have a problem them pursue
air filtering. Best regards,

Mary-Lou Florian


                                  ***
                  Conservation DistList Instance 15:11
                  Distributed: Thursday, July 12, 2001
                       Message Id: cdl-15-11-002
                                  ***