Cold-chain logistics is the business of storing and moving food and medicine at controlled temperatures, from the maker's plant to the shop or the pharmacy shelf. It uses cold stores, which are refrigerated warehouses, and refrigerated trucks, often called reefer trucks. Its job is to keep the cold chain, the unbroken series of cold stores and cold vehicles, from breaking at any point.
India produces a great deal of food that must stay cold: milk, fruit, vegetables, fish, meat and ice cream. A large share of its fruit and vegetables is lost every year because it is not kept cool on the way to market. Medicines matter too. Vaccines, insulin and many newer medicines must stay between 2 °C and 8 °C, and some must be kept far colder.
A cold-chain company runs three kinds of site. A cold store holds goods for weeks or months, often at minus 18 °C or below for frozen food. A distribution centre receives large loads and sends smaller ones on to shops, pharmacies and dark stores. And the trucks between them must hold the same temperature all the way, even when their doors open at each stop.
The newest cold stores are automated. Working inside a store at minus 25 °C is hard on people, who can stay inside only for short spells. In an automated cold store, cranes on rails put pallets away in racks up to 30 metres high and bring them back when they are ordered, as in an automated storage and retrieval system (AS/RS). Because no one walks between the racks, the racks can stand close together, and less cold air is lost.
Take a frozen-food company that makes parathas and frozen peas near Sonipat, in Haryana. It sends 22 pallets a day to an automated cold store nearby, kept at minus 22 °C. Each pallet's barcode is scanned at the door, and a crane stores it. A supermarket chain in Delhi orders three pallets for the next morning. At 4 a.m., the crane brings them to a loading dock kept at minus 18 °C. A reefer truck carries them to the chain's distribution centre. Loggers record the temperature every few minutes on the way, through cold-chain monitoring, and the record goes with the delivery.
Medicines add one more need: each pack must be traceable. Drug makers give each pack its own serial number through serialisation and track-and-trace, and the cold-chain company records the serial numbers of every box it stores and ships. An online pharmacy that sells insulin must keep it cold up to the customer's door, often in an insulated box with an ice pack.