The occurrence of mold on wood pallets has received increasing attention in recent years from pallet suppliers, their customers and the U.S. Department of Agriculture.
Some suppliers have found themselves in situations where customers have returned a truck-load of pallets because of the presence of mold. Manufacturers do not want mold from pallets contaminating their packaging nor their products.
Virginia Tech, home of the Center for Unit Load Design and its affiliated pallet laboratory, sponsored a conference on preventing and eliminating mold on hardwood pallets in 2007. It dealt with such topics as the science of mold, mold on wood, chemical treatment, preventing and eliminating mold on pallets, a pallet manufacturer’s case study, and more.
A Georgia company with experience providing solutions for mold for the home building industry has developed a coating product for wood pallets and containers to prevent mold. Its products already have been used successfully by pallet and sawmill businesses.
The company, X-Mold, is a division of X-M Industries. Ron Jones, a principal of the company, is a research scientist specializing in antimicrobial development. Ron had more than 10 years of experience in the pest control industry before turning his attention to mold. He founded X-M Industries in 1997 and developed a patented treatment to prevent moisture and termites in synthetic stucco.
In 2005 the company added mold resistant coating products for the home building industry, which was becoming ensnared in lawsuits because of mold in new homes. X-Mold’s comprehensive mold protection program for homes offers protection for the skeletal framing, drywall and other cellulosic surfaces found in a house. The X-Mold division has become a leading provider of preventative pre-treatment programs and mold mitigation products to home builders, and its mold resistant coating products for homes are warranted for up to 25 years.
The product developed by X-Mold for the pallet and container industry is marketed under the brand name E-Fusion-RTU.
Preventing mold on pallets is particularly important for shipments of such products as paper, food and pharmaceuticals, noted Ron, so that the products themselves are not contaminated by mold. Businesses that export products also are interested in preventing mold on pallets.
Mold spores are present in all outdoor and indoor environments, noted Ron. They can begin to grow immediately on freshly sawn wood, and application systems can be fabricated to treat freshly sawn cut stock or other material.
Pallets should be treated as soon as possible after manufacture. Spraying systems can be installed in-line after a nailing machine to automate the treatment process.
E-Fusion is a water-thin coating that seals the wood so mold cannot contact the wood, explained Ron. It can be applied with a brush, garden sprayer or other spray or dip tank and dries within 15-30 minutes. After treatment, pallets should be stored out of the rain.
One gallon of E-Fusion will treat 25 pallets at a cost of pennies per pallet, according to Ron. E-Fusion is typically sold in 55-gallon drums or 5-gallon pails. It is available in concentrated form and also as a ready-to-use product.
E-Fusion can be used on pallets (new or recycled) or lumber where mold already has occurred, but it does not eliminate mold nor remove staining. Any existing mold should be removed first by sanitizing with a standard disinfectant or power washing. E-Fusion seals the wood so existing mold cannot expand further and prevents new mold from occurring on the coating surface.
“You can treat any wood at any time,” said Ron. “Preferably, you want to treat it before you get the problem.”
X-Mold also can add different color dyes to E-Fusion to produce a colored pallet. “It’s not the same as latex paint, but it’s more like a stain,” said Ron. Some companies want to differentiate their pallets, he noted. Dyes are available in any color.
E-Fusion can be used for heat-treated pallets, too, said Ron. It can be applied either before or after heat-treatment. “Heat-treating does not affect the chemical,” he said.
The heat-treating process actually makes wood pallets or lumber more susceptible to mold, according to Ron. The process pushes moisture and sugars to the surface of the wood. The pallets come out of the heat-treating chamber hot and wet – ideal conditions to grow mold. Frequently, they are put in sheds or other places to cool, and fans are used to blow air on them, which can carry mold spores to the pallets.
Ron has worked successfully with about 10-15 pallet and sawmill businesses that experienced mold on pallets or lumber. E-Fusion effectively eliminated their mold problems. “Some are now starting to treat all their pallets as a pro-active measure,” he said.
One pallet manufacturer that has used E-Fusion with good results is Pallet Makers in Hartsville, S.C. “If your customers require mold-free pallets, I suggest you call X-Mold,” said Hamlet Fort, president of Pallet Makers, “because they have quality products and people. They have a product that really works, and they bent over backwards to help me.”
Ron has been working with Automated Machine Systems (AMS) to develop an electrostatic spraying system for pallets. The system applies a negative electrical charge to the chemical so that it is attracted to and bonds to the wood, which has a positive electrical charge. The system will coat “every square inch except where the pallet is nailed together,” said Ron, and reduces chemical usage by 70%. It also will have features to capture the overspray so none of the chemical is wasted and will have no impact on the environment, he said.
E-Fusion RTU was tested by the Virginia Tech Center for Unit Load Design, and the researchers found that it provides effective protection against mold.
Samples of green Southern yellow pine, oak and yellow poplar were dip treated in E-Fusion for about 30 seconds, according to a report by Peter Hamner and Marshall (‘Mark’) White. Then the samples, along with some untreated samples, were inoculated with three types of common mold spores. The samples were maintained in a chamber at 86 degrees and 100% humidity.
Standard test methods for fungicides prescribe a four week testing period. X-M Industries requested a test period of 12 weeks. Because of the increased time interval, the center inoculated the samples with mold spores again after 10 weeks to evaluate the long-term efficacy of treatment; a second treatment of E-Fusion was not applied.
“No visible mold was observed during this 10 week duration,” the study authors wrote in their report. “In contrast, the untreated samples had abundant mold growth that began forming in the early stages of the test. For pallet manufacturers and their customers who are concerned about mold growing on pallets, the E-Fusion product manufactured by X-M Industries provides excellent protection that should last long enough for pallet surfaces to dry below 20% moisture content.”
Trace amounts of mold were visible on the treated samples two weeks after the second inoculation of mold spores, showing the efficacy of E-Fusion declined over time.
“As indicated,” the authors wrote, “the intent of using a chemical fungicide on pallets is to prevent mold protection while pallets have time to dry. The
mold protection provided by E-Fusion exceeds this requirement for most
conditions of pallet use. Pallets must be protected from subsequent exposure to water.”
(For more information about E-Fusion, contact X-Mold at (866) 581-6653 or visit the company’s Web page at www.xmold.net; the Virginia Tech report also may be downloaded from the same Web page. For more information about spray systems, call Automated Machine Systems at (877) 267-8384).
