Practical tips for avoiding mold on imported shoes

Quality Control TipsEarlier this week, I published a post entitled “Avoiding humidity inside containers“. It started with a client’s problem:

Last week, an importer was asking us how to avoid the formation of mold on the shoes they ship from China to Chile. The goods stay up to 50 days inside the container, so that was an extreme case.

This morning I received some insightful comments from a packaging expert, Kevin Howard. I already published some of his advice in the past (for example, about packaging optimization) and I am always blown away by the depth of his experience.

Here are his tips for this situation:

Humidity in ocean containers from Asia has been a problem ever since there have been ocean containers, but there are some really effective ways to minimize and/or eliminate such issues, sometimes without the use of desiccants.

First though, you should know a little more about how desiccants work. Did you notice on the Superdry site that their test data for effectiveness was based on a sealed chamber? A sealed chamber controls the exact amount of humidity/moisture available to the desiccant, while an ocean container is not air tight. As a result, it would be difficult/impossible for desiccant to really absorb all the moisture available in an ocean container.

Also, when thinking of the volumetric space of an ocean container, one should remember that it’s possible to displace much of that volume by densely packing the container with products. Unfortunately, shoes are not very dense, nor is the package surrounding shoes. This type of product and packaging make for a worse case condition, but there are ways to mitigate the situation.

The most effective use of small packs of desiccants can be found on items like cameras that have tight fitting packaging surrounding them. Some cameras use molded expanded polystyrene foam (EPS) that fully encapsulates the camera. By creating this kind of foam box, only a small amount of desiccant is needed to absorb moisture found in the cavity of that foam. If the shoe manufacturer needs to use desiccants, it would be wise for them to use plastic bags to tightly surround a few boxes at a time, thus limiting the amount of free air space that the desiccant must act upon. If they could pull a vacuum on the bag, they’d have even less moisture left in the void spaces.

Many companies don’t realize they are introducing moisture into the system by the types of materials they use. Many Chinese boxes are soft and not very dense and have a higher moisture content than materials found in the US. If the shoe manufacturer is using the cheapest possible box material, which not only starts with high moisture content, but also absorbs moisture like a sponge as it travels through the distribution system, then they are placing moisture-sensitive products in a moisture-absorbing/producing material. The same goes with pallets. I have seen a number of times where pallets from Asia produced a tremendous amount of humidity in ocean containers. Replacing wood pallets with plastic slip sheets eliminated the problem, plus allowed more products per container.

The shoe manufacturer may want to consider not using boxes for ocean shipment, along with eliminating pallets (if they were using them). If they shipped each pair of shoes in individual sealed bags with a small amount of desiccant, they’d be able to increase load density by a significant percentage while eliminating the humidity issue. They would need to postpone the packaging operation until the shoes arrive in Chile, but the savings in damages, handling, storage and shipping would pay for having a packaging line in Chile. Postponing the packaging would also allow this company to provide different sku’s to different customers, all based on different packages for those specific customers. With the costs of ocean containers continuing to climb, it’s more important than ever for companies to consider ways to densify their products as much as possible, and postponing the packaging is oftentimes a viable way to do just this.

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