3 ways of saving your mouldy wooden pallets

 

Wooden pallets are a valuable commodity in their own right, and far too many are prematurely scrapped. This is neither environmentally nor economically sensible because most are easy to repair and recondition. Professionally reconditioned wooden pallets are often as strong and hygienic as new ones and refurbished pallets also offer significant cost savings.

A common problem is the slow (or sometimes sudden) appearance of fungal colonies or mildew stains. This can happen on new as well as older pallets and although it often affects pallets left in the rain or stored without air circulation, it is also common on pallets that have travelled for weeks in containers or cargo holds. It does not usually mean that the pallet was improperly conditioned to begin with, nor that it is no longer fit for use. Understanding the problem will help keep those pallets in use for longer.

Pallet construction

Some people assume that inferior or even scrap timber is used to construct pallets. This is far from the case, the timber is carefully chosen, quality graded and often receives elaborate treatments in accordance with internationally defined standards. Those treatments improve their durability and destroy almost all kinds of infestation - insect, fungal or bacterial - that might be present.

One of the most common treatments is with heat, usually in a large kiln or sometimes with microwaves. Heat serves two purposes: it hardens the wood, making it more durable and also kills the vast majority of possible insect pests or other organisms like moulds. Ironically, however, heat treatments also drive moisture from inside the wood out onto its surface, and with it are carried trace amounts of naturally occurring sugars. As a result, although the new pallet is sterile internally, its surface is quite hospitable, under the right environmental conditions, for future growths to take hold. In fact, newly heat-treated pallets can be more susceptible to surface mould than older refurbished pallets.

Are reconditioned wooden pallets safe?

Although some moulds can be toxic if ingested, it is important to keep the problem in perspective. Mould colonies grow from spores that are ubiquitous in the air we breathe, day in day out. Spores are very, very small and therefore remain airborne almost indefinitely, rising high into the stratosphere and spreading easily around the world - no pallet necessary. Whenever you store or transport goods in any way, it is always necessary to consider the conditions they need and mould risk may or may not be a high priority among other considerations.

If your goods are adequately protected from the risks of airborne mould, they are highly unlikely to be infected from mould on a pallet. Although there are occasional claims that the smell of musty pallets has penetrated goods, investigation nearly always determines that the culprit is the storage conditions to which both were exposed or the choice of an inappropriate chemically treated pallet. Nevertheless, mould stains on pallets are always unwelcome but there are several ways to clean them and safely re-use reconditioned wooden pallets.

 

Let us list 3 ways here:

First, be aware that not all stains on wood are caused by mould. The action of the sun, contact with rust, natural wood enzymes and a host of other things can cause marks to develop that are often mistaken for mould. That is little comfort if your customer still isn't happy but mould treatments won't help.

Secondly, if the pallet is not used for a sensitive commodity, such as foodstuffs, it is often sufficient to pressure-wash the pallet. Spraying them with vinegar or dilute bleach about a half hour beforehand will help to kill surface spores and loosen the discolouration. They should then be thoroughly dried as quickly as possible (this is important).

If the stains soon reappear it may be because moisture deep in the pallet has allowed mould to penetrate. In this case, the only real solution is to re-sterilise them by heat treatment. It is far safer to let a professional pallet services company do this for you than risk igniting or under-heating them with makeshift equipment.

The final option is to apply a chemical treatment - but only if this is allowed by your (and your customer's) industry standards. Again, it is better to consult a pallet specialist than to risk choosing an inappropriate chemical.