Cold chain

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.

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Uses

Cold chains are common in the food and pharmaceutical industries and also some chemical shipments. One common 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.

This is important in the supply of vaccines to distant clinics in hot climates served by poorly developed transport networks. Disruption of a cold chain due to war may produce consequences similar to the Smallpox outbreaks in the Philippines during the Spanish-American war.

Traditionally all historical stability data developed for vaccines was based on the temperature range of 2-8 °C. With recent development of biological products by former vaccine developers, biologics has fallen into the same category of storage at 2-8 °C due to the nature of the products and the lack of testing these products at wider storage conditions.

Validation

A cold chain can be managed by a quality management system: it can be analyzed, measured, controlled, documented, and validated. The food industry uses the process of Hazard Analysis and Critical Control Point, HACCP, as a useful tool. Its usage continues into other fields. PDA (Parenteral Drug Association) Technical Report # 39 gives a rough summary of how the cold chain can be validated.

The overall approach to validation of a distribution process is by building more and more qualifications on top of each other to get to a validated state. This is done by executing a Component Qualification on the packaging components. Next, an Operational Qualification that demonstrates the process performs at the operational extremes. The final piece is the Performance Qualification that demonstrates that what happens in the real world is within the limits of what was demonstrated in the Operational Qualification limits.

The PDA’s Technical Report states that a Component Qualification is required to demonstrate that a component can be manufactured to the design criteria of that individual component. This was put into the document because the industry did not understand the principles of Validation; all Validation processes were specific to equipment and not auxiliary processes such as shipping/distribution.

Performing thermal testing can also help with validating the cold chain. Certified test labs use environmental chambers to simulate ambient profiles that a package may encounter in the distribution cycle. Thermocouple probes measure temperatures within the product load to assure that temperatures do not reach outside of the required temperature range. Testing can be completed in triplicate based on a qualification protocol to create a final qualification report that can be used to defend the configuration when audited by the FDA. It is normally best to have an individual that understands the principles of Validation, when defending such processes to a Federal Regulatory body of any nation.

Cold chains need to be evaluated and controlled.

• Carriers and logistics providers can assist shippers
• The use of Refrigerator trucks, Refrigerator cars, Reefer (ship)s, Reefer (container)s, and refrigerated warehouses is common.
• Shipment in insulated shipping containers or other specialised packaging
• Temperature data loggers help monitor the temperature history of the truck, warehouse, etc and the temperature history of the product being shipped.
• Documentation is critical

During the distribution process one should monitor that process until one builds a sufficient data set that clearly demonstrates the process is in compliance and in a state of control. Each time the process does not conform to the process, a Non Conformance or Deviation should document each event. Those events should be properly investigated and mitigated so that they do not occur on future shipments. Thus the process is continually evolving and correcting for anomalies that occur in the process. Eventually the process can evolve into periodic monitoring once sufficient data demonstrates that the process is in a state of control. Any anomaly that occurs once a process is in a state of control will result in the process being invalidated and not in control and result in product withdraw from the market to ensure patient safety.

It is necessary to develop an internal documentation system as well as multi party communication standards and protocalls to transfer or create a central repository or hub to track information across the supply chain. These systems would monitor equipment status, product temperature history, and custody chain, etc. These help ensure that a food, pharmaceutical, or vaccine is safe and effective when reaching its intended consumer.

See also

• Bacterial growth
• HACCP
• Insulated shipping container
• Logistics
• Packaging
• Shelf life
• Specification
• Temperature control
• Thermal decomposition
• Thermal insulation
• Tolerance (engineering)
• Transportation management system
• United States Pharmacopeia
• Validation (drug manufacture)
• Verification and Validation

External links and resources

• "Manual on the Management, Maintenance and Use of Blood Cold Chain Equipment", World Health Organization, 2005, ISBN 9241546735
• "Cold Chain Management", 2003, 2006, [1]
• Clive, D., "Cold and Chilled Storage Technology", 1997, ISBN 0751403911
• Australia Cold Chain Center, [2]
• EN 12830:1999 Temperature recorders for the transport, storage and distribution of chilled, frozen and deep-frozen/quick-frozen food and ice cream
• Parenteral Drug Association [3]
• Mike Magee, comments on November 16, 2007 Copenhagen conference on the Cold Chain. [4]
• Ray Cowland, Developing ISTA Cold Chain Environmental Standards, 2007, [5]