The cold chain is the unbroken sequence of temperature-controlled storage and transport that keeps a product within its required temperature range from production to use. For frozen fruit that range is -18 degrees Celsius or colder. A cold chain is only as strong as its handovers – the moments when goods move between parties or environments.
Where it breaks
Not inside a running reefer. It breaks on ambient docks, during loading and unloading, at cross-docks, during customs inspection, and at the intake bay of the receiving warehouse. These are exactly the points where nobody is recording, because each party assumes the other is.
Making it verifiable
A cold chain that cannot be evidenced is a cold chain you cannot defend commercially. The minimum evidence set is a pre-cooling record, a product core temperature at loading, a continuous log in the load, and a product core temperature at intake. Name in the contract which record prevails and who downloads it.
See cold chain logistics for the route-level view, and cold chain management for frozen exports for the controls.