Gel Packs vs. Dry Ice: Tips to Shipping Seafood

whole salmons lying iced transportation box
 

Whether you are transporting your latest catch from your most recent fishing expedition or you are shipping large quantities of seafood to your customers, the biggest problem shipping live or frozen seafood is spoilage.

There are several ways you can keep your seafood fresh during transport, but the two most common methods are with dry ice and gel packs. However, it can be difficult to know which coolant is best for your shipping needs. So, here are some tips on how to use each one.

Use the Right Coolant for the Job


Both dry ice and gel packs have their benefits and their drawbacks when it comes to shipping seafood. The first step to ensuring your seafood stays fresh and intact during transit is by selecting the right coolant.

Dry ice should only be used when shipping frozen products as the temperature inside the insulation will drop well below 34 degrees F (0 C). This makes it ideal for shipping snap frozen seafood products over a short duration.

Gel packs are a great alternative to standard cube ice as they keep fresh seafood, such as live shellfish, alive without the mess of melting into water. They are also a more cost-effective way to keep your product cool while shipping.

In some cases, you may need to use a combination of dry ice and gel packs. The gel packs stabilize the dry ice causing it to sublimate at a slower rate and effectively extending the shelf-life of both the coolant and the product. This is ideal for long-haul shipping over several days and works for seafood products that can be frozen and then thawed before they reach their destination.

assorted sea food bed ice

Use a Good Insulator


The key to long-lasting freezing and refrigeration during transport is a good quality insulated container. The standard container for shipping perishables is the insulated Styrofoam container which comes in a variety of sizes and wall thicknesses and works well with both dry ice and gel packs.

However, not all Styrofoam boxes are created equal. For shipping live or frozen seafood, you need a container that keeps the interior as cool as possible to reduce the amount of coolant lost. The best way to assess the insulating properties of the container is by checking the R-factor, which refers to how much the material resists thermal change. The higher the R-factor, the better the insulation.

Use the Correct Ratio of Coolant to Product


The effectiveness of both coolants diminishes over time. Dry ice changes from solid to gas through the process of sublimation and gel packs return to their semi-liquid state inside the bag.

To ensure your seafood products don't spoil part-way through transit, you need to pack enough coolant in with the product to control the temperature and minimize the loss of coolant. The amount of each coolant depends on the amount of product you are shipping, the container you use and the expected duration of transport.

For dry ice, you can expect to use 5 to 10 pounds of dry ice for a 15-quart container for 24 hours. For gel packs, it is recommended you use one pound of gel packs for each cubic foot for every 24 hours. If you are shipping larger volumes, simply multiply the amount of coolant by these ratios.

Keep Coolant and Product Separate


While coolants keep your seafood products fresh during transit, they can also damage your product if they come into contact. This is especially important when using dry ice as the chemical composition and extreme low temperatures can change the texture and taste of the product.

When shipping frozen seafood with dry ice, ensure the products are securely sealed; vacuum packing is ideal. Live seafood does not need additional packaging to be shipped with gel packs, but fresh or thawed packaged seafood products shipped with gel packs can be subject to water damage from condensation in the gel packs as they melt.

Minimize Packing Time


To get the most life out of your coolants, reduce the packing time as much as possible. This keeps both the product and the coolant at an optimal even temperature before departure, ensuring your product stays fresher for longer.

As an additional precaution, pack your foam shipping container inside a walk-in freezer or another cold environment to reduce the amount refrigerant lost and always take care when handling dry ice. It is a hazardous material that can damage your skin, so wear protective gloves when packing it inside the container.

fresh fish sale market

Fill the Empty Space


Voids in the shipping container contribute to faster loss of refrigerant and put your seafood products at risk of spoilage. Minimize the space between coolant and products by adding additional packing materials to the space.

Place product and gel packs as close together as possible. For the best results with dry ice, pack dry ice on the bottom of the container, followed by a layer of gel packs, then the product, then additional gel packs and dry ice on top. Use Styrofoam packing peanuts, bubble wrap or newspapers to fill in any gaps.

Be Aware of Government Regulations


Unlike gel packs, dry ice is considered a hazardous material, which means it is subject to additional shipping regulations, especially when traveling by air. The benefit to gel packs is there are no restrictions on the quantity you can use when shipping by air.

However, to be certain you comply with federal and international shipping regulations regarding seafood and other perishables, consult the FDA website and the International Air Transport Association's publication on Perishable Cargo Regulations.

Final Thoughts


To keep your seafood safe during transit, it is essential you use the right coolant, container and packing method to suit your mode of shipment and shipping duration. Both dry ice and gel packs are effective for keeping your seafood products cool, just be sure to choose the right one for the job so your customers can enjoy high-quality seafood.

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