Pallet mold is a major concern for manufacturers in a wide variety of industries. Not surprisingly, the food & beverage and pharmaceutical industries have always been concerned about mold on the pallets that they use, but purchase managers in many industries are starting to look at pallets with increased scrutiny as well. While mold has a minimal effect on the lifespan of the pallet itself, it can damage a manufacturer’s products, contaminate their production lines, and may even pose a health risk in the form of increased risk of asthma attacks for those who are sensitive to mold.
Pallet mold can be a serious problem, but the good news is that steps can be taken to prevent, inhibit, and remediate mold on wood pallets.
While there are many different molds, for the purpose of this discussion, mold is a type of fungus that produces pigmented spores and grows on the surface of wood products (among other things). There are literally thousands of molds that can land on a wood surface and grow. These fungi feed on the structural polymers, sugars, and proteins in the wood and generally produce spores that can become airborne. Some of these spores are clearly visible in black, white, green, orange, or purple spots, while others are not visible to the naked eye.
These spores can easily spread to other damp surfaces, including other woods products. Depending on the mold species, surfaces available, and environmental conditions, spores can grow and spread in a few days, but can also take months or even years to spread and grow.
The type of wood you use for your pallets and crates can also affect your risk of mold. Wood species with more stored sugars are at a higher risk, but no untreated wood is completely free from the risk of mold without proper care.
Mold presents on wood surfaces when conditions are favorable for growth. It requires four key elements to order to take root, survive and grow:
1. Moisture
In order for mold to grow on pallets, crates, and other wood packaging, it must have moisture. In general, pallets stored in a location with 60% humidity or greater have a better chance of becoming contaminated, but it’s not impossible for mold to grow in conditions with far less humidity. The moisture level of the wood itself also plays a role. Wood with greater than 19% moisture content also encourages mold growth. Your wood packaging should never be built from green or wet wood.
2. Oxygen
Mold requires oxygen to take root and grow. For obvious reasons, it’s impossible to control the oxygen levels in areas where wood or wood products are stored. On the other hand, vacuum-sealing products stored on wood pallets can help reduce the risk contamination.
3. Temperature
Many types of mold are capable of growing in a wide range of temperatures as long as moisture is present. In general, however, mold grows best in warm temperatures. Ideal temperatures for mold growth are between 70 and 85 degrees fahrenheit.
4. Food Source
If all other conditions are met with regard to moisture, oxygen, and temperature, the wood in your wood packaging becomes an ideal food source for many types of mold. Unfortunately, mold will also feed on the products that are stored on your pallets and crates. Nearly anything that contains natural sugars and proteins can become food for mold as well, including apparel, food & beverage products, pharmaceutical products, toys, household items, etc.
The best way to prevent mold from growing on your pallets, crates, and wood packaging is to stop it before it has a chance to start. As we’ve already discussed, pallet mold needs four key things to survive: moisture, oxygen, ideal temperatures, and food. For obvious reason, we can’t limit its food supply – the wood itself. It’s also unrealistic to try to limit the oxygen that surrounds pallets.