Pallet Mold: 7 Tips To Prevent Mold On Wood Pallets

In this article we will we continue our discussion about pallet mold by exploring handling and storage best practices, discerning the difference between mold and wood stain, as well as briefly touching upon the opportunity for chemical treatment of pallets as an alternative solution. Here, then, are some more crucial quick tips.

How do you prevent pallet mold?

1. That trailer just arriving with your pallets – think of it as an incubator. A dark, humid trailer for pallet storage is a recipe for trouble. It can easily turn into an unintended science experiment, Keith Reinstettle, Vice President, Sales at PalletOne Inc. observes wryly. Remove pallets as quickly as possible, he encourages. Coordinate pallet unit load arrival with your pallet supplier and plan internal space available so that they can be unloaded quickly, and placed into appropriate storage.
2. Don’t stage pallets outside in the rain, even for a little while. Even brief exposure to water can pose problems. As one researcher notes, “Free water may only be present on the wood surface for a short period of time, but it may only take a few days for a fungus to germinate, grow into the wood, and produce spores on the surface. The wood may already be dry by that time, but the damage will already be done.”
3. Store pallets in a dry, well lit, and ventilated location. For covered outdoor storage, orient the pallet ends of stringer pallets in the direction of the prevailing wind to maximize airflow. For indoor storage, there can be a tendency to stack pallets in the dankest and darkest corner of the facility. While space is almost always at a premium, it is crucial to choose a ventilated location with better light.
4. Maintain pallet row spacing to ensure circulation. Orient pallet openings in the direction of airflow and leave a space between the rows of pallet stacks. This approach is especially important where stringer pallets are stacked side by side, as stringers act as a barrier to airflow. Air velocity as low as a few feet per second can deter mold growth, according to experts. Additionally, elevating stacks of pallets 6 to 8 inches above the floor helps eliminate contact with any puddles of rainwater. 
5. Treat an occurrence of pallet mold as a non-conformity in your quality process. Instituting a corrective and preventive action (CAPA) can help pinpoint the root cause of the event and hopefully lead to a lasting resolution to the problem. Research might point to underlying issues such as staffing availability, a forklift operator training gap or a lack of available covered storage space.
6. Understand the difference between stain and mold. Your problem might not be mold at all. Take Bluestain, for example, which creates a bluish or greyish discoloration in the wood. Bluestain is not associated with human health concerns or performance issues. To determine if you are dealing with mold or Blustain, lightly rub the affected surface of the wood. According to a recent NWPCA brochure, “Mold grows on the surface and can be brushed off or smeared, whereas blue stain penetrates deep into the wood and cannot be removed.”  Bluestain, iron stain and other natural defects are discussed in greater detail in the brochure.
7. Consider chemical treatment, if accepted in your supply chain. There is a range of EPA registered as well as FDA approved or exempted ingredients that can be formulated and applied to best meet the needs of your application. Check with your pallet supplier for more details.

Best way to ensuring mold-free pallets

In summary, the best way to ensuring mold-free pallets is to source dry pallets from a leading pallet supplier, and take precautionary measures during unloading and storage to keep pallets dry and well ventilated – especially once the warmer days of spring arrive. Understand the difference between mold and stain, and consider a chemical treatment if allowed. By applying these basic practices as outlined above, you can go a long way toward ensuring problem-free pallets for your supply chain.

Quick Tips for Mitigating Mold on Pallets

If you missed the first article on pallet mold, ‘Quick Tips for Mitigating Mold on Pallets‘ give it a read. We talked about the importance of vendor selection and explained why, contrary to popular belief, heat treatment is not an effective approach to restricting mold growth. We also looked at how softwood pallets might be a better option than hardwood if you have mold problems, and why companies should increase vigilance each and every year as the warmer weather of Spring arrives.