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ne of the challenges faced by the pallet manufacturing industry is mold prevention. The need for mold prevention strategies is growing as food safety requirements change and worker environmental conditions are further scrutinized. The purpose of this article is to explain why mold grows on pallets, and present solutions that pallet manufacturers can implement. Mold Growth and Moisture Mold has a purpose in our ecosystem, i.e. to consume dead organic material. For this reason, mold spores are everywhere in our environment. Mold thrives both indoors and outdoors and is sustained by wood and wood products; paper and other paper products like cardboard and wallpaper; leather; fabric and upholstery; grout; painted walls; cement; plaster (drywall); ceiling tiles; insulation materials; and carpet. In addition to a constant food source, there are a few other key ingredients mold needs to thrive which are: 1. Temperature, ideal growing conditions are between 41 and 100 degrees Fahrenheit. 2. Oxygen 3. Moisture Of the three conditions required for mold growth, moisture is one element that manufacturers can try to control. According to Ralph Rupert, manager unit load technology, Millwood Incorporated: "Mold can only grow when there is free water in the cells of the wood. Moisture causes more problems with wood than all other issues combined." Rupert explained that water may reside in wood as follows: • Free water – liquid water in cell lumens • Water vapor – water vapor in cell lumens • Bound water – water inside cell wall The fiber saturation point, the point where no more free water remains and bound water is at maximum (28 to 30 percent moisture content, typically) is a key benchmark when considering moisture content. Mold can be prevented in wood that is below the fiber saturation to around 20 percent. Kiln drying and air drying are both options in reducing the moisture content below the required level. Other Key Considerations According to Jeff Morrell, professor at Oregon State University's College of Forestry, Wood Science & Engineering Department, moisture reduction is not a failsafe option: O BLOG Pallet Mold Prevention Strategies 34 PalletCentral • March-April 2017 palletcentral.com