A cold chain is a temperature-controlled supply chain. An unbroken cold chain is an uninterrupted series of storage and distribution activities which maintain a given temperature range. It is used to help extend and ensure the shelf life of products such as fresh agricultural produce, seafood, frozen food, photographic film, chemicals, and pharmaceutical drugs.
Cold chains are common in the food and pharmaceutical industries and also some chemical shipments. One commom temperature range for a cold chain in pharmaceutical industries is 2 to 8°C, but the specific temperature (and time at temperature) tolerances depend on the actual product being shipped.