Mold – It is Not Just For Breakfast Anymore!

Ever so often a question comes up regarding books and mold. I attended a presentation in 2007 on this subject. I thought I would share some of what I learned. These are notes that I took, so the sentence structure may not be the best.

This was a presentation given by Michele Brown from Cornell University and sponsored by ASLS at the NYLA Conference in Buffalo in October 2007. Her e-mail if you have any questions about mold:

Molds are fungi. Mildew is a smaller form of mold. For our purposes mold and mildew are the same thing. Mold needs to absorb carbon from other substances in order to live. Mold spores are the way that mold reproduces and spreads. This is what we are concerned with stopping. These spores land on something and grow out and forms a colony. If moisture is taken away at this stage, the vegetative part will die, but the spores will remain.

It is difficult to kill spores. Mold spores are smaller than pollen. Mold spores are between 1 and 20 microns in size. Good air circulation is important – if the mold spore can not land – it can not germinate. Mold spores have their own toxins. For activation it needs to have sufficient moisture and food.

There are molds that can extract moisture out of the air. Black mold needs to land on a substrate that is constantly wet. Mold releases toxins when it germinates. This is when you start to see the staining on the materials that have been attacked by molds. It is also digesting the product at that point.

Molds thrive in damp areas. Mold can grow behind the walls even if it looks like the building is dry. There is an infared therma graph that can see mold in between the walls. Mold is a little plant – it sends out little roots into whatever it is growing on.

Mold can grow on the side of houses on Latex paint. 75% of dust is composed of dead or dormant mold spores. Mold can grow inside of us. Molds like to eat cellulose (paper, cloth). Contact from adjacent moldy material will make it spread. It can be spread through contaminated solutions used for cleaning or mixing. Spores can live in Lysol.

Inside a building the most common spores are aspergillus and penicillium. Attracted to cloth, animal fur, and fibers. Xerophilic can extract moisture from the air. These are the types we find in libraries. Cloth and paper are permanently weakened and stained. Active mold is still growing. If you rub it – it will leave a smear. Inactive mold looks like dust. Both will cause an allergic reaction.

If you have an occurrence of inactive mold – wipe the pages with 70% alcohol, this will wipe up the spores. Book still looks the same after it as been cleaned. Once an item has had a mold growth – it is likely to happen again when you have a spike in humidity. Anything that is going to kill mold spores (chemical wise) is not good for your health. Reaction to mold cause a weakening of your immune system. Flu like symptoms, loss of memory, tremors, hallucinations… A book about this subject is “Poisons of the Past” Mary Kilbourne Matossian. She believes an infection of the rye flour by the ergot fungus was responsible for hallucinations which were the basis of the witchcraft trials.

Keep humidity below 60% to not spread. Dry – humid – dry – humid cycles are good for mold spores. Important to maintain a constant temperature and humidity level. Use a dehumidifier. You can smell mold (mildew smell) – this smell is different than an old book smell. You can also see it. Treat all mold as a health hazard.

Spores will start germinating within 24 hours. Colonies will develop within a few days. If there is a flood turn on fans and dehumidifiers in the first 24 hours. This will make it that the spores can not land and will start to dry out the air. If you can not get the materials dried in 24 to 48 hours – it should be frozen. Freezing the materials stops the mold from growing. Freeze dried – would stop mold growth and take out moisture.

Keep books at 68 – 72 degrees F. Keoep dust out of collections. Make sure humidity is less than 60% humidity. Unpack old books away from your collection. If you have a box that smells suspect, put in a room with a dehumidifier. You need to lower the humidity to make active mold become inactive.

If you have an outbreak: Locate source of moisture Immediately start drying the room and the books out. Determine size of the outbreak. If a book is wet – put it on a table with a fan on it. Use glove (nitrol gloves), masks (N95 or N100 rated), non-vented goggles, aprons or something that you can throw away immediately after you are done. You don’t want to take the mold spores with you.

Isolate the moldy materials to another room or drape plastic around the area. Should be a well ventilated area. Mold must be inactive before you can remove it. Lower the humidity. Dry any wet materials and surfaces are dry (direct fans). Try to keep a book by wiping the powdery substance off with alcohol and cheese cloth or vacuum it with a HEPA vacuum or disposable static cloth. The over the counter alcohol is better than the industrial grade alcohol. Clean the area thoroughly. Use cleaning solution with bleach. Dry thoroughly. Make sure any carpet is completely dry before returning the books to the stacks. Discard all the cleaning cloths and everything you wore and used and throw them away.

Keeping books packed tightly prevents the air and space needed for mold to grow. Foxing – mold circles in the paper – actually molding on the metal that is contained in some paper. After a book is cleaned of mold keep it out of the collection for at least a week until you put it back in to the stacks. Air conditioner blowing on the books – causes mold. Cold air can hold a lot of moisture if it is humid.

Resources: A webpage devoted to resources about mold. Emergency Salvage of Moldy Books and Paper. Northeast Document Conservation Center Preservation Leaflets. Lab Safety Supply General Conservation Supplies General Conservation Supplies Freeze drying of wet materials Freeze drying of wet materials (recently did some work for Lourdes Hospital in Binghamton, NY) Freeze drying of wet materials.


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