Mold

The following is posted with the knowledge of the author, Harriet A.
Burge, PhD, Associate Professor, Environmental Microbiology, Harvard
School of Public Health.  Dr. Burge has been extremely gracious in
discussing her views on the flood at Colorado State University
Library, where 425,000 books from the circulating collection were
severlye water damaged this past July.  Due to a lack of consensus
in the field regarding the treatment of masses of non-rare library
material affected by mold, I have found her comments extremely
useful in outlining a protocol for addressing the problem, and pass
them along in the hopes of stimulating further discussion on the
topic.

Dr. Burge wrote:

1.  How much mold is acceptable on library books?  I don't know.
    Certainly visible, living mold is not acceptable, nor is
    sufficient active mold growth so that moldy odors are evident.
    There is no data on which to base surface measures.  I usually
    consider surfaces that are not visibly moldy and produce 1 or 2
    colonies/square inch that are of mixed types, then the surface
    is "normal".  This is predicated on sampling considerably more
    than one square inch of surface!  On the other hand, if a
    surface sample produces an essentially pure culture of one
    fungus with more than 20 colonies from the area sampled, then I
    would guess that active growth is still occurring.  These are
    only rule of thumb guidelines.  I interpret each sample as it
    comes, and take many factors into consideration.

2.  Sterilant:  I only have experience with ethylene oxide.  I would
    not consider using paraformaldehyde.  Levels necessary to kill
    fungi are far in excess of those safe for people, and I would be
    worried about residual formaldehyde in the pages of books.  I
    have no experience with other methods.

3.  Spore viability:  The reason for sterilizing is to prevent
    continued growth, not to reduce risk.  Dead fungi contain
    allergens and toxins as well as live ones.  Do you need to
    vacuum all the books? [i.e.,using a vacuum equipped with HEPA
    (high efficiency particle) filter)]  Probably not. Those with
    visible growth are the most likely to contain releasable spores.
    Often water stains can be present with no visible growth, and I
    have used a severely water-stained mycology book that was
    damaged in a flood for many years with no adverse effects.  It
    was freeze-dried following the flood, but no other treatment was
    used.

    I don't know how long mold remains "dangerous"--mold spores are
    designed to be resistant, and may last a long time.  I don't
    think the allergens would last long, however.  They are
    proteins, and probably degrade with some rapidity, although no
    one has the slightest idea (as far as I know) what the time
    course might be for a dry spore.  Mold allergen extracts can
    lose potency within weeks.

    I do think, in the end, that you will have to warn asthmatic
    people of potential exposures in this particular part of the
    library. Also, you will HAVE TO keep the place completely dry
    forever after.

4.  Fanning pages:  One possibility for books with relatively
    minimal mold growth:  If they were "used" (i.e., the pages
    turned rapidly) in a fume hood with the door mostly closed, most
    loose spores would be released, and relatively little additional
    exposure could be expected.

I'm sorry I can't be more specific, and I know this isn't very
satisfactory with respect to concrete guidelines.  The fact is that
very little real research has been conducted in this area.  Have you
seen our paper on Fungi in Libraries?  Ref:  Burge et al. Fungi in
libraries: an aerometric study.  Mycopathologia 1978; 64(2):67-72.
Feel free to post our conversations.  Maybe someone will have better
ideas than I.

Harriet

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                  Conservation DistList Instance 11:44
                 Distributed: Friday, November 14, 1997
                       Message Id: cdl-11-44-001
                                  ***