Reefers Used to Ship Perishable Cargo
September 1, 2021
Refrigerated containers or reefers are used to ship perishable goods such as flowers, dairy products, meat, seafood, and fruits and vegetables.
Carriers also use temperature-controlled containers to transport frozen and chilled goods, photographic film, and pharmaceuticals. If not shipped at appropriate humidity and temperature, such cargo might spoil quickly during transit.
Reefer Design
Reefers have one or more temperature chambers and a generator to maintain the right temperature regardless of weather conditions. Depending on the type of cargo, the temperature ranges from – 35 °C to 35 °C. As they are used for refrigeration transport, cooling gets done during loading, storage, and transit.
Air is blown through the side or floor of the reefer. The floor is typically T-styled, with air coming from the bottom up to cool cargo.
There are also refrigerated containers that use water to maintain the desired temperature. They have a water cooling system that ventilates heat in the storage space and outside the containers.
Types of Reefers
The main types of refrigerated containers in use are automatic fresh air management, controlled/modified atmosphere (CA/MA), and closed reefers. The latter have automatic heating and cooling units and come as a single piece. These are conventional containers.
Automatic fresh air management reefers are equipped with an advanced air exchange system to adjust the composition of gases, including carbon dioxide and oxygen. Controlled/modified atmosphere reefers also have an air exchange system that replaces the used oxygen to maintain the atmosphere inside containers constant.
Types of Cargo
Reefers are used to ship chilled goods such as live plants, confectionary, eggs, and seafood. Chilled goods are transported at temperature around freezing points to retain their value. Frozen goods also require specialized transportation at temperatures of -20°C and below. Examples are prepared foods and concentrates, frozen meat, and ice cream which are shipped at freezing temperatures to retain their quality, texture, and flavor. Low temperatures slow down oxidation processes and enzyme activity and prevent bacterial growth.
Reefers are also used for miscellaneous and special cargo such as chemicals, tobacco, pharmaceuticals, and batteries. In most cases, such cargo has special handling instructions for humidity and temperature control, stowage, and packaging.
The approximate shelf life depends on the type of cargo to be transported. It is 2 to 3 weeks for avocados, 1 to 7 months for apples, and 7 to 10 days for green beans.
Cargo Handling
Before shipping, forwarders provide information such as humidity and temperature requirements, type of packaging, destination and departure port, weight and volume, and types of products shipped. This information allows carriers to ensure the appropriate conditions and identify the right container and ship to transport cargo.
Chilled and frozen goods are pre-cooled to maintain the appropriate temperature and are placed in containers and loaded through a cold tunnel facility. Cargo is packaged using strong cartons and is packed tightly so that it is stable. Reefers are then set to maintain the appropriate humidity and temperature and to maintain proper ventilation.
