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How to Mail Frozen Food: Your Guide to Cold Chain Shipping

In eCommerce shipping, sellers are responsible for maintaining timelines, ensuring package protection throughout the entire delivery, and fighting to keep shipping costs low. However, those who list frozen food must contend with additional concerns as well, such as how to deliver products at the correct temperature.

Mailing frozen food brings unique considerations like temperature control, packaging, humidity, and compliance with rules for dry ice and food quality. That’s on top of the individual requirements of shipping carriers. To keep food at the desired temperature, you’ll need robust packaging and preparation so your goods arrive frozen.

How to mail frozen food

Mailing frozen food requires thorough planning and preparation to avoid humidity issues, freezer burn, and other problems that threaten the integrity of a shipment’s contents.

1. Product prep

Frozen foods need packaging that protects both the consumables inside and the box itself. At a minimum, you’ll need to wrap every item in your freezer in plastic. It’s good practice to incorporate this as a regular part of product prep in your warehouse. For example, MyFBAPrep can shrink-wrap items quickly using our shrink-wrap machines to ensure products spend minimal time outside of the freezer before moving to the next fulfillment stage.

2. Packaging

The best packaging for frozen food is a multi-layer solution consisting of:

  1. Shrink-wrap
  2. Dry ice
  3. Gel packs
  4. Packing material to prevent movement
  5. Polystyrene boxes
  6. Unsealed box liners
  7. Cardboard boxes

Packaging liners are important to prevent boxes from getting wet. However, you can’t seal packaging liners because dry ice releases carbon dioxide, which may build up pressure and burst if it’s unable to escape the package.

Depending on your budget, you might want to use cold packs or insulated foam planks instead of polystyrene. Your packaging has to protect the food, insulate the coolant, and support the box so your package reaches the customer in peak condition. Some products also require special treatment; for example, it’s best to double-bag seafood.

3. Temperature control and coolants

Sellers have a few options to maintain adequate temperature when mailing frozen food:

  • Dry ice: The coolant of choice for mailing frozen goods. However, you have a five-pound maximum of dry ice per package for air flights and certain carriers. An insulated five-pound block of dry ice will stay frozen for up to 24 hours. That normally ensures food arrives frozen within about 36 hours, if properly insulated.

If you ship with a carrier that doesn’t have a dry ice weight restriction, 8–10 pounds of dry ice can keep your food frozen for up to 48 hours.

  • Gel packs: A strong option for keeping your food between 32 and 60 degrees Fahrenheit. However, new innovations now enable certain gel packs to keep your food completely frozen. These are normally sold with their temperature rating in the name, such as “10℉.”

If you need to keep food frozen for more than 48 hours, it’s best to mix dry ice with gel packs.

  • Reefer trucks: If you routinely deliver large amounts of frozen food to the same area, working with a direct-to-consumer delivery fleet of refrigerated vehicles may save you considerably on packaging and coolant costs. This approach works best primarily if you ship to localized areas from a single distribution point, or if volume for a specific area is especially high so you establish a single delivery day for that region.

4. Labeling

Frozen food requires strict and transparent labeling to stay compliant with shipping carriers. That entails:

  • Clearly disclosing the use of dry ice with a UN-1845 Class 9 label on the package and listing the weight
  • For air transportation, a declaration for dangerous goods
  • Labeling food as frozen (or, if the food is intended to arrive thawed, label it “Thawed”)
  • An explicit list of all frozen goods contained in the parcel on the outside of the packaging

5. Shipping methods and planning

Your shipping carrier plays a big role in the success of mailing frozen food, and different services have different recommendations, requirements, and costs. The carrier you choose must guarantee your frozen foods arrive at their destination within 48 hours of shipment. Popular options include:

  • USPS: Possesses services to ship frozen food via air or ground transport, provided you follow their requirements:
    • Clearly mark and label boxes.
    • Don’t exceed five pounds of dry ice for air transportation (dry ice allowed at any amount for surface transportation) and add a warning label.
    • Produce (i.e., frozen fruits and vegetables) are prohibited from shipment to Florida, California, and Hawaii.
  • UPS: UPS has almost exactly the same shipping restrictions as USPS. You’re limited to 5.5 pounds of dry ice by air but can ship more via ground transportation, and you must also clearly mark packages. USPS Worldwide Economy is available to ship internationally, but there are additional fees and unique requirements.
  • FedEx: FedEx has somewhat stricter requirements for shipping dry ice:
    • The maximum dry ice quantity is 440 pounds.
    • You must call your local FedEx office ahead of time to ensure they accept dry ice since FedEx requires employees to take hazardous chemical training to handle it.
    • Use labeling as listed above.
    • Exterior packaging must be fiberboard (corrugated cardboard), plastic, or wooden boxes. You may not use FedEx-branded boxes.
  • DHL: DHL offers cold chain shipping solutions like reefer trucks and liquid nitrogen-cooled shipments, as well as options to ship with dry ice. You must label your dry ice package as previously discussed, and shippers must have IATA training and comply with IATA P1650.

You’ll also want to consider distribution, time of shipping, and expected delays. Normally, that means distributing your frozen foods so they can arrive anywhere in your service area within a maximum of 48 hours but preferably sooner.

Implement real-time tracking where possible so you can immediately see when delays happen and move replacement and refund processes forward.

Wrapping up — Mailing frozen food requires precision and attention to detail

Mailing frozen food requires purchasing an appropriate coolant, investing in robust packaging and labeling, and meeting individual carrier requirements. For most eCommerce sellers, that necessitates working with a 3PL. Experienced providers can move items quickly from cold storage and provide insulted packaging and shipping to minimize costs while ensuring products arrive safely and still frozen.

MyFBAPrep can help with the specific product prep, cold storage, and even shipping products at the right time to arrive ready to eat, depending on your business model. If you’d like to learn more about how we can guide you through every stage of cold chain shipping, don’t hesitate to contact us.