A cold chain is only as strong as its weakest link. Milk, ice cream, frozen meat, seafood, vaccines and many medicines must stay within a defined temperature band at every step: production, cold storage, refrigerated transport, distribution warehouse, retail display or clinic refrigerator, and finally the point of use. A break at any step, such as a van left in the sun or a shop cooler switched off at night, can damage the product even if every other step was perfect.
Cold chains are managed with appropriate equipment at each step, temperature monitoring and records, clear handling procedures for loading and unloading, and plans for power cuts and breakdowns. In pharma, the cold chain is tightly controlled and documented; in food retail, it is increasingly expected by brands and auditors.
An ice cream brand distributing across Rajasthan relies on frozen storage at the plant, refrigerated trucks to depots, and display freezers at thousands of shops. If a shopkeeper switches off a freezer overnight to save power, the product refreezes with ice crystals, and the customer gets a grainy tub.