{{short description|Low-temperature supply chain}} {{Use dmy dates|date=November 2020}} thumb|Cold chain being maintained using ice box while transporting polio vaccine {{food safety}}
A '''cold chain''' is a supply chain that uses refrigeration to maintain perishable goods, such as pharmaceuticals, produce or other goods that are temperature-sensitive.<ref name="WHO">{{cite web |title=The Vaccine Cold Chain |url=https://www.who.int/immunization/documents/IIP2015_Module2.pdf |access-date=19 December 2020 |website=www.who.int |publisher=WHO}}</ref> Common goods, sometimes called '''cool cargo,'''<ref>Lou Smyrlis (19 September 2013). [http://www.ctl.ca/news/cns-claude-mongeau-preaches-eco-system-of-collaboration-at-port-days/1002607171/ "CN's Claude Mongeau preaches 'eco-system of collaboration' at Port Days"] {{webarchive|url=https://web.archive.org/web/20130921054734/http://www.ctl.ca/news/cns-claude-mongeau-preaches-eco-system-of-collaboration-at-port-days/1002607171/|date=21 September 2013}}, Canadian Transportation Logistics, Retrieved 20 September 2013</ref> distributed in cold chains include fresh agricultural produce,<ref name="CTFVPx">{{cite web |last=Kohli |first=Pawanexh |title=Fruits and Vegetables Post-Harvest Care: The Basics |url=http://crosstree.info/Documents/Care%20of%20F%20n%20V.pdf |archive-url=https://web.archive.org/web/20110114150117/http://crosstree.info/Documents/Care%20of%20F%20n%20V.pdf |url-status=dead |archive-date=14 January 2011 |access-date=6 April 2009 |publisher=CrossTree techno-visors}}</ref> seafood, frozen food, photographic film, chemicals, and pharmaceutical products.<ref>{{Cite journal |last=Gyeszly |first=S. W. |title=Total System Approach to Predict Shelf Life of Packaged Food Products |url=https://www.astm.org/stp14842s.html |journal=Food Packaging Technology |date=1991 |language=en-US |publisher=ASTM International |pages=46–50 |doi=10.1520/STP14842S|isbn=0-8031-1417-6 |url-access=subscription }}</ref> The objective of a cold chain is to preserve the integrity and quality of goods such as pharmaceutical products or perishable goods from production to consumption.<ref>{{cite web | url=https://www.paho.org/en/immunization/cold-chain | title=Cold Chain - PAHO/WHO | Pan American Health Organization }}</ref><ref>{{Cite web |title=Cold Chain and Logistics Management. Immunization Handbook |url=https://cdn.who.int/media/docs/default-source/searo/india/publications/immunization-handbook-107-198-part2.pdf |access-date=2025-10-30 |website=World Health Organization}}</ref><ref>{{Cite web| title=Cold chain and logistics management | url=https://www.who.int/docs/default-source/searo/india/publications/immunization-handbook-107-198-part2.pdf | archive-url=https://web.archive.org/web/20220710075706/https://www.who.int/docs/default-source/searo/india/publications/immunization-handbook-107-198-part2.pdf | archive-date=2022-07-10}}</ref>
A well functioning, or unbroken, cold chain requires uninterrupted sequence of refrigerated production, storage and distribution activities, along with associated equipment and fleet management logistics, which maintain a desired low-temperature interval to keep the safety and quality of perishable or sensitive products. Unlike other goods or merchandise, cold chain goods are perishable and always en-route towards end use or destination. Adequate cold storage, in particular, can be crucial to prevent food loss and waste.<ref>{{Cite book|url=http://www.fao.org/documents/card/en/c/ca6122en|title=The State of Food and Agriculture 2019. Moving forward on food loss and waste reduction, In brief|publisher=FAO|year=2019|location=Rome|pages=12}}</ref>
==History== Mobile refrigeration with ice from the ice trade began with reefer ships and refrigerator cars (iceboxes on wheels) in the mid-19th century.<ref>{{Cite web |title=FRIDGE SPACE - Bibliothèque et Archives Canada |url=https://central.bac-lac.gc.ca/.item?id=TC-BVAU-969&op=pdf&app=Library&oclc_number=1033137690}}</ref> The term ''cold chain'' was first used in 1908. The first effective cold store in the UK opened in 1882 at St Katharine Docks.<ref name="Install new cold storage"/> It could hold 59,000 carcasses, and by 1911 cold storage capacity in London had reached 2.84 million carcasses.<ref name="Install new cold storage"/> By 1930 about a thousand refrigerated meat containers were in use which could be switched from road to railway.<ref name="Install new cold storage">{{cite book |last1=Otter |first1=Chris |title=Diet for a large planet |date=2020 |publisher=University of Chicago Press |location=USA |isbn=978-0-226-69710-9 |page=45 }}</ref>
Mobile mechanical refrigeration was invented by Frederick McKinley Jones, who co-founded Thermo King with entrepreneur Joseph A. "Joe" Numero. In 1938 Numero sold his Cinema Supplies Inc. movie sound equipment business to RCA to form the new entity, U.S. Thermo Control Company (later the Thermo King Corporation), in partnership with Jones, his engineer. Jones designed a portable air-cooling unit for trucks carrying perishable food,<ref name="Minnesota Hall of Fame"/> for which they obtained a patent on 12 July 1940,<ref name="Black Firsts">{{cite book | url=https://books.google.com/books?id=93SDBwAAQBAJ&pg=PA613 | title=Black Firsts: 4,000 Ground-Breaking and Pioneering Historical Events | publisher=Visible Ink Press | author=Smith, Jessie Carney | year=2012 | pages=613 | isbn=978-1-57859-424-5}}</ref> subsequent to a challenge to invent a refrigerated truck over a 1937 golf game by associates of Numero's, Werner Transportation Co. president Harry Werner, and United States Air Conditioning Co. president Al Fineberg,<ref>[https://archive.org/details/eightblackameric00hayd ''Eight Black American Inventors'' by Robert C. Hayden] Addison-Wesley, 1972; pp. 46- 50.</ref><ref name="Minnesota Hall of Fame">{{cite web | url=http://www.msthalloffame.org/frederick_mckinley_jones.htm | title=Frederick McKinley Jones | publisher=Minnesota High Tech Association / Science Museum of Minnesota | work=Minnesota Science and Technology Hall of Fame | access-date=11 February 2010}}</ref><ref name="Black Firsts"/><ref>{{cite web|url=http://www.greatachievements.org/?id=3864|title=Air Conditioning and Refrigeration History - part 4 - Greatest Engineering Achievements of the Twentieth Century|website=www.greatachievements.org|access-date=24 April 2018|url-status=live|archive-url=https://web.archive.org/web/20161203195802/http://www.greatachievements.org/?id=3864|archive-date=3 December 2016}}</ref>
This technology has been frequently in use since the 1950s, when it was most often used for preserving animal-based cells or tissue. As medical breakthroughs, such as in cancer treatment, have taken place, the demand for cold chain systems has grown. The COVID-19 pandemic and its associated vaccinations, have caused vastly increased need.<ref name="Kelly">{{cite web |last1=Kelly |first1=Kate |title=Critical to Vaccines, Cold Storage Is Wall Street's Shiny New Thing |url=https://www.nytimes.com/2020/12/15/business/cold-storage-covid-vaccine.html |website=The New York Times |access-date=20 December 2020 |date=15 December 2020}}</ref>
==Uses== Cold chains are common in the food and pharmaceutical industries and also in some chemical shipments. One common temperature range for a cold chain in pharmaceutical industries is {{convert|2|to|8|C}}, but the specific temperature (and time at temperature) tolerances depend on the actual product being shipped.<ref>{{cite web |title=Unit Blogarticle: Choosing the right Medical Refrigerator |url= https://www.swisslog-healthcare.com/en-gb/company/blog/choosing-the-right-medical-refrigerator-or-freezer |access-date= 22 January 2026 }}</ref>
===Produce=== Unique to fresh produce cargoes, the cold chain requires to additionally maintain product specific environment parameters<ref name="CTFVPx"/> which include air quality levels (carbon dioxide, oxygen, humidity and others).{{cn|date=August 2023}}
===Vaccines=== The cold chain is used 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 or logistical challenges may produce severe consequences, as distributed vaccines can become inert due to a lack of temperature control during transport.<ref name="alexcode914">{{cite web|url=http://history.amedd.army.mil/booksdocs/wwi/communicablediseleases/chapter9.html|title=Office of Medical History|website=history.amedd.army.mil|access-date=24 April 2018|url-status=dead|archive-url=https://web.archive.org/web/20170216235803/http://history.amedd.army.mil/booksdocs/wwi/communicablediseleases/chapter9.html|archive-date=16 February 2017}}</ref> The integrity of the vaccine cold chain is therefore a critical public health concern.<ref>{{cite web |url=https://nccvmtc.org/PDF1/1_036.pdf |title=The Cold Chain |publisher=National Center for Cold Chain Management |access-date=23 September 2025 |format=pdf}}</ref>
For vaccines, there are different types of cold chains. There is an ultralow, or deep freeze, cold chain for vaccines that require -70 degrees C, such as the Ebola and Pfizer–BioNTech COVID-19 vaccines, and some animal vaccines. Next the frozen chain requires -20 degrees C. Varicella and zoster vaccinations require this level. Then the refrigerated chain, which requires temperatures between two and eight degrees C. Most flu vaccinations only require refrigeration.<ref name="Fischetti"/>
In 2020, during the COVID-19 pandemic, vaccines being developed may need ultracold storage and transportation temperatures as cold as {{convert|-70|C}}, requiring what has been referred to as a "colder chain" infrastructure.<ref name="dereklowe1">{{cite journal|author=Derek Lowe|url=https://www.science.org/content/blog-post/cold-chain-and-colder-chain-distribution|title=Cold Chain (And Colder Chain) Distribution|date=31 August 2020|access-date=5 September 2020|journal=Science Translational Medicine}}</ref> This creates some issues of distribution for the Pfizer vaccine. It is estimated that only 25 to 30 countries in the world have the infrastructure for the required ultracold cold chain.<ref name="Fischetti">{{cite web |last1=Fischetti |first1=Mark |title=The COVID Cold Chain: How a Vaccine Will Get to You |url=https://www.scientificamerican.com/article/the-covid-cold-chain-how-a-vaccine-will-get-to-you/ |website=www.scientificamerican.com |publisher=Scientific American |access-date=20 December 2020 |archive-url=https://web.archive.org/web/20201219072939/https://www.scientificamerican.com/article/the-covid-cold-chain-how-a-vaccine-will-get-to-you/ |date=19 November 2020|archive-date=19 December 2020}}</ref>
== Technologies == thumb|left|Truck with cooling system The integrity of a modern cold chain is maintained by a suite of interconnected technologies that provide real-time monitoring, data logging, and operational control. These systems are a key part of Fleet digitalization and are essential for ensuring product safety, regulatory compliance, and operational efficiency. The development of advanced frameworks for temperature monitoring, leveraging IoT platforms, has become a key area of innovation in logistics.<ref>{{cite journal |url=https://www.researchgate.net/publication/377776203_Enhancing_Cold_Chain_Logistics_A_Framework_for_Advanced_Temperature_Monitoring_in_Transportation_and_Storage |title=Enhancing Cold Chain Logistics: A Framework for Advanced Temperature Monitoring in Transportation and Storage |author1=A. K. M. F. U. Islam |author2=J. Suhonen |date=February 2024 |journal=Journal of Engineering and Applied Sciences |volume=15 |issue=1}}</ref>
=== Fleet Telematics and Remote Monitoring === Refrigerated trucks, railcars, and reefer containers are typically equipped with advanced fleet telematics systems. A telematic control unit installed in the vehicle or container serves as the central hub for data collection. Unlike standard systems, these units often interface directly with the refrigeration unit's microprocessor, allowing for two-way communication. This enables dispatchers and fleet managers to not only receive data but also remotely adjust settings, such as the temperature setpoint.
The specialized telemetry data transmitted in real-time is crucial for cold chain oversight. This includes: * '''Vehicle location data''': Real-time GPS tracking for continuous visibility of the asset's location. * '''Temperature Monitoring''': Data from multiple sensors placed inside the trailer or container to ensure uniform temperature distribution. * '''Reefer Unit Status''': Critical operational data such as the temperature setpoint, return air temperature, operating mode (e.g., continuous vs. start/stop), and any active alarm codes from the refrigeration unit. * '''Door Sensors''': Alerts that are triggered whenever cargo doors are opened or closed, helping to monitor security and prevent unnecessary temperature excursions.
=== Data Logging and Compliance === Continuous data logging is fundamental for validation and compliance. This is achieved using standalone Temperature data loggers, RFID tags that record temperature, or, most commonly, through the integrated telematics system. This creates an unbroken digital record of a shipment's temperature history from origin to destination, which is the core of a modern '''Track and trace''' system.<ref>{{cite web |url=https://geoplanph.com/wialon-the-key-to-grupo-bafars-successful-cold-chain-monitoring-transformation-in-retail-stores/ |title=Wialon: The Key to Grupo Bafar’s Successful Cold Chain Monitoring Transformation in Retail Stores |website=Geoplan |access-date=23 September 2025}}</ref> This verifiable audit trail is essential for meeting regulatory standards like HACCP and Good Distribution Practice (GDP), and for accurately determining the remaining shelf life of a product.<ref>{{cite journal|last=Meyers|first=T|date=June 2007|title=RFID Shelf-life Monitoring Helps Resolve Disputes|journal=RFID Journal|url=http://www.rfidjournal.com/article/articleview/3357/1/128/|url-status=dead|archive-url=https://web.archive.org/web/20090630083639/http://www.rfidjournal.com/article/articleview/3357/1/128/|archive-date=30 June 2009}}</ref>
=== Route Planning and Driver Management === Modern route planning software can optimize routes not only for time and fuel efficiency but also to minimize risks to temperature-sensitive cargo. This can include avoiding areas with high ambient temperatures or known traffic congestion that could strain refrigeration units. Furthermore, Driver scoring systems are used to monitor driving behavior. Gentle driving with smooth acceleration and braking is important to prevent load shifting and damage to delicate products like fresh produce or pharmaceuticals.
=== Video Telematics and Security === For high-value cargo, '''video telematics''' systems with interior and exterior-facing cameras provide an additional layer of oversight. This technology can be used to verify that proper loading and unloading protocols are followed to minimize the time cargo doors are open. It also enhances security, which, when combined with GPS tracking, is a critical component for the Stolen vehicle recovery of valuable shipments such as pharmaceuticals.
== See also == {{div col|colwidth=35em}} * Automatic vehicle location * Bacterial growth * Dashcam * Dry ice * Fleet digitalization * Fleet telematics system * Frank Vale, cold storage pioneer * GPS tracking unit * HACCP * Insulated shipping container * Intelligent transportation system * Journey planner * Packaging * Phase-change material * Pharmaceutical distribution * Shelf life * Stolen vehicle recovery * Telematic control unit * Telemetry * Temperature control * Temperature data logger * Time temperature indicator * Track and trace * Thermal decomposition * Thermal insulation * Tolerance (engineering) * Transportation management system * ULT freezer * United States Pharmacopeia * Vaccine storage * Validation (drug manufacture) * Vehicle location data * Vehicle tracking system * Verification and validation * Video telematics {{div col end}}
== Sources == {{Free-content attribution | title = The State of Food and Agriculture 2019. Moving forward on food loss and waste reduction, In brief | author = FAO | publisher = FAO | page numbers = 24 | source = | documentURL =http://www.fao.org/documents/card/en/c/ca6122en | license statement URL = https://commons.wikimedia.org/wiki/File:The_State_of_Food_and_Agriculture_2019._Moving_forward_on_food_loss_and_waste_reduction,_In_brief.pdf | license = CC BY-SA 3.0 }}
==References== {{reflist}}
== Further reading == {{refbegin}} * {{Cite book |last1=Brecht |first1=Jeffrey K. |last2=Sargent |first2=Steven A. |last3=Brecht |first3=Patrick E. |last4=Saenz |first4=Jorge |last5=Rodowick |first5=Leonard |year=2019 |title=Protecting Perishable Foods During Transport by Truck and Rail. Supersedes USDA Handbook 669 of 1995. Document HS1328 of the Horticultural Sciences Department, Institute of Food and Agricultural Sciences, University of Florida |url=https://edis.ifas.ufl.edu/publication/HS1328 |accessdate=2023-05-09 }} * Brian Lassen, "Is livestock production prepared for an electrically paralysed world?" J. Sci. Food Agric. 2013;93(1):2–4, Explains the vulnerability of the cold chain from electricity dependence. * ''Manual on the Management, Maintenance and Use of Blood Cold Chain Equipment'', World Health Organization, 2005, {{ISBN|92-4-154673-5}} * Pawanexh Kohli, "Fruits and Vegetables Post-Harvest Care: The Basics", Explains why the cold chain is required for fruits and vegetables. * Clive, D., ''Cold and Chilled Storage Technology'', 1997, {{ISBN|0-7514-0391-1}} * EN 12830:1999 Temperature recorders for the transport, storage and distribution of chilled, frozen and deep-frozen/quick-frozen food and ice cream * Ray Cowland, Developing ISTA Cold Chain Environmental Standards, 2007. * {{Cite book |last=Rees |first=Jonathan |year=2013 |chapter=Chapter 1: Inventing the cold chain |title=Refrigeration Nation: A History of Ice, Appliances, and Enterprise in America |series=Studies in Industry and Society |publisher=Johns Hopkins University Press |isbn=9781421411064 |pages=11–30 }} * Nordic Cold Chain Solutions, Manufacturer of temperature-controlled packaging, [http://www.nordiccoldchain.com nordiccoldchain.com]--> {{refend}} {{food preservation}}
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{{DEFAULTSORT:Cold Chain}} Category:Supply chain management Category:Fleet management Category:Logistics Category:Food safety Category:Temperature control Category:Cooling technology Category:Drug distribution Category:Packaging Category:Ice in transportation Category:Pharmaceutical industry