How to Ship Refrigerated (Reefer) Cargo

By Erick Hudson · Published 11 November 2026 · 11 minute read

Refrigerated cargo needs more than a container with a cooling unit. A successful reefer shipment starts with the correct product temperature, suitable packaging, a realistic transport specification and a loading plan that allows air to circulate through the cargo. Get any of those wrong and a technically sound refrigeration unit may still deliver poor results.

Reefer containers are used for chilled and frozen food, produce, meat, seafood, dairy, pharmaceuticals and other temperature-sensitive goods. This guide explains how to prepare and book one, what happens during transit, and the checks Australian importers and exporters should make. For a wider look at container equipment, start with the shipping container guide.

What a reefer container does

A reefer is an insulated container fitted with a refrigeration unit. It circulates conditioned air through the load and uses controls to maintain the agreed transport conditions while connected to an appropriate power source. The unit is not a substitute for proper product preparation. It should not be treated as a blast freezer or as a way to pull warm cargo down to its required core temperature during the voyage.

Reefer equipment is built for different cargo requirements. A standard refrigerated unit may be suitable for many chilled or frozen commodities, while some products require specialised settings, controlled-atmosphere equipment or other handling arrangements. Availability and technical capability vary by carrier and trade lane, so describe the commodity accurately when requesting a quote.

Step 1: Establish the cargo specification

Before requesting a booking, obtain a written handling specification from the producer, manufacturer or responsible cold-chain manager. It should identify the correct carrying temperature, acceptable tolerance, ventilation or fresh-air exchange requirement, humidity needs where relevant, and any restrictions on mixed loading. Do not choose a temperature simply because it is common for a similar product.

Different varieties, maturity levels, packaging systems and processing states can have different requirements. Chilled produce, frozen meat, seafood and pharmaceuticals cannot be treated as one generic temperature category. A set point that is suitable for one commodity may damage another. The carrier can confirm whether its equipment can meet the requested range, but the shipper remains responsible for giving accurate cargo instructions.

Step 2: Book the right equipment and service

Provide the forwarder or carrier with the commodity name, quantity, gross mass, dimensions, packaging type, loading location, origin and destination, required set point and intended transit window. Also state whether the shipment needs temperature recording, remote monitoring, a data logger, controlled atmosphere or any special plug-in arrangements at depots and terminals.

Confirm the route and the points where the container will be powered. A reefer may need electrical connection during terminal storage and transhipment. Ask who monitors alarms, who receives alerts and what happens if the equipment loses power or the vessel schedule changes. The booking confirmation should record the agreed settings rather than leaving them to be interpreted from informal messages.

Step 3: Prepare the product before loading

Bring the cargo to its required transport temperature before it is stuffed. This is one of the most important practical controls in reefer shipping. Loading warm product into a container set to a colder temperature can create a large heat load, prolong pull-down, affect neighbouring packages and leave the cargo exposed to unsuitable conditions even while the unit is running normally.

Where possible, use a refrigerated loading bay and keep the time with doors open to a minimum. Check that the reefer is clean, dry, free from odours and in sound condition. A carrier's pre-trip inspection (PTI) checks the container and refrigeration machinery before use; ask whether the allocated unit has passed the required inspection and whether any repair or re-test is outstanding.

Step 4: Load for airflow, not just cubic capacity

Cold air needs a defined path through the load. In many reefer containers, supply air moves through the floor channels and around the cargo before returning to the refrigeration unit. Blocking that path creates uneven conditions and can leave hot spots in parts of the shipment. A load that fills every available gap may look efficient but can perform badly in transit.

• Keep cargo within the marked load line and do not obstruct the return-air space near the ceiling.
• Do not cover or block the T-bar floor channels; load only within the floor area intended for cargo.
• Stow cartons evenly and consistently so air can move through the designed channels.
• Use packaging that protects the product without creating an unintended vapour barrier or sealing off airflow.
• Secure the load against movement without crushing cartons or blocking air passages.
• Follow the specific loading diagram and limits supplied for the allocated equipment.

Hapag-Lloyd's reefer cargo handling guidance illustrates the importance of pre-cooled product, correct stowage and unobstructed air circulation. Carrier instructions should be checked for the actual unit and commodity.

Step 5: Confirm settings and records

Before the doors are closed, verify that the set point, ventilation and humidity settings match the shipping instructions. The required settings must be based on the commodity specification, not a default copied from a previous booking. Record the container number, seal number, loading time, product temperature checks and any relevant photographs.

Temperature evidence can come from several sources: the reefer unit's controller records, a carrier monitoring service, independent data loggers or cargo-level sensors. These records do not all measure the same thing. A supply-air reading describes air leaving the unit; a return-air reading reflects air coming back from the load; a pulp or product probe measures the cargo itself. Agree which data will be available and how it will be supplied if a claim or quality investigation is needed.

Transit, power and contingency planning

Reefer containers require dependable power at relevant points in the journey. A vessel may have reefer slots, while terminals and depots use powered connections. Transhipments, vessel delays, port congestion and inland transfers can all extend the time in the supply chain. Ask the forwarder to explain which party is responsible for monitoring at each stage and how an alarm or loss of power is escalated.

Build a practical contingency plan around the nature and value of the goods. Identify the contacts who can authorise action, the acceptable temperature excursion limits, the evidence that must be preserved and the process for notifying insurers or receivers. Do not assume that a temperature alarm automatically means the product is ruined, or that a normal unit reading proves every carton remained within specification. Product assessment should follow the relevant quality and safety protocol.

Australian import considerations

Cold-chain compliance does not replace Australian import controls. For food imports, check the commodity in the Department of Agriculture, Fisheries and Forestry's BICON system before shipping. Some goods are prohibited, while others need permits, treatment, supporting documents or specific import conditions. Food intended for sale must also meet Australian food standards and may be referred to the Imported Food Inspection Scheme.

Confirm requirements before the goods leave the supplier. A shipment can arrive in excellent temperature condition and still be delayed because its import conditions or supporting documents have not been met. For timber pallets, crates and dunnage, check the applicable timber and bamboo packaging conditions as well.

Common reefer shipping mistakes

• Using the reefer to cool warm cargo. Pre-cool the product to its required carriage temperature before loading.
• Blocking airflow. Do not load above the line or obstruct floor channels and air returns.
• Guessing the set point. Obtain written instructions for the exact commodity and product state.
• Ignoring ventilation. Fresh-air exchange is commodity-specific; too much or too little can affect quality.
• Failing to plan for delays. Confirm power arrangements and who responds to alarms at transhipment and terminals.
• Assuming one temperature reading tells the whole story. Know whether the record is supply air, return air or actual product temperature.

Frequently asked questions

What temperature should I set a reefer container to?

There is no safe universal setting. Use the product's approved carriage specification, which may vary by commodity, variety, maturity, processing and destination. Confirm it with the producer or responsible cold-chain specialist and record it in the booking instructions.

Can a reefer freeze fresh produce?

It can maintain a below-zero setting if designed and configured for that purpose, but that does not make it suitable for every product. Many fresh commodities are chilled above freezing and can suffer chilling or freeze damage outside their required range.

Does a reefer run without electricity?

The refrigeration unit needs a suitable power supply to operate continuously. Some transport equipment may provide power during road movements, but availability depends on the carrier, vehicle and service. Confirm every powered and unpowered leg before booking.

Should I leave ventilation open?

Only when the commodity specification calls for it. Fresh-air exchange requirements differ by product and transport method; use the agreed instruction rather than a generic rule.

Protect the cargo before it enters the container

Reliable reefer transport is built around the product, not just the machinery. Start with a verified cargo specification, pre-cool correctly, select suitable equipment, protect the air path, record the settings and make sure somebody is responsible for monitoring the shipment. For more on how equipment choices affect cargo handling, return to the shipping container guide or read how to pack and load cargo to prevent damage.