A cold chain is a low temperature-controlled

supply chain In commerce, a supply chain is a network of facilities that procure raw materials, transform them into intermediate goods and then final products to customers through a distribution system. It refers to the network of organizations, people, activ ...

network. An unbroken cold chain is an uninterrupted series of refrigerated production, storage and distribution activities, along with associated equipment and logistics, which maintain quality via a desired low-temperature range. It is used to preserve and to extend and ensure the

shelf life Shelf life is the length of time that a commodity may be stored without becoming unfit for use, consumption, or sale. In other words, it might refer to whether a commodity should no longer be on a pantry shelf (unfit for use), or no longer on a ...

of products, such as fresh agricultural

produce Produce is a generalized term for many farm-produced crops, including fruits and vegetables ( grains, oats, etc. are also sometimes considered ''produce''). More specifically, the term ''produce'' often implies that the products are fres ...

, seafood,

frozen food Freezing food preserves it from the time it is prepared to the time it is eaten. Since early times, farmers, fishermen, and trappers have preserved grains and produce in unheated buildings during the winter season. Freezing food slows decompositi ...

photographic film Photographic film is a strip or sheet of transparent film base coated on one side with a gelatin emulsion containing microscopically small light-sensitive silver halide crystals. The sizes and other characteristics of the crystals determine ...

, chemicals, and pharmaceutical products. Such products, during transport and end-use when in transient storage, are sometimes called cool cargo. Unlike other goods or merchandise, cold chain goods are perishable and always en-route towards end use or destination, even when held temporarily in cold stores and hence commonly referred to as "cargo" during its entire logistics cycle. Adequate cold storage, in particular, can be crucial to prevent quantitative and qualitative food losses.

History

Mobile

refrigeration The term refrigeration refers to the process of removing heat from an enclosed space or substance for the purpose of lowering the temperature.International Dictionary of Refrigeration, http://dictionary.iifiir.org/search.phpASHRAE Terminology, ht ...

with ice from the

ice trade The ice trade, also known as the frozen water trade, was a 19th-century and early-20th-century industry, centering on the east coast of the United States and Norway, involving the large-scale harvesting, transport and sale of natural ice, and ...

began with reefer ships and

refrigerator car A refrigerator car (or "reefer") is a refrigerated boxcar (U.S.), a piece of railroad rolling stock designed to carry perishable freight at specific temperatures. Refrigerator cars differ from simple insulated boxcars and ventilated boxcars (co ...

s (

icebox An icebox (also called a cold closet) is a compact non-mechanical refrigerator which was a common early-twentieth-century kitchen appliance before the development of safely powered refrigeration devices. Before the development of electric refrige ...

es on wheels) in the mid-19th century. The term ''cold chain'' was first used in 1908. The first effective cold store in the UK opened in 1882 at

St Katharine Docks St Katharine Docks is a former dock and now a mixed-used district in Central London, in the London Borough of Tower Hamlets and within the East End. It lies on the north bank of the River Thames, immediately downstream of the Tower of London an ...

. It could hold 59,000 carcasses, and by 1911 cold storage capacity in London had reached 2.84 million carcasses. By 1930 about a thousand refrigerated meat containers were in use which could be switched from road to railway. Mobile mechanical refrigeration was invented by Frederick McKinley Jones, who co-founded

Thermo King Thermo King is an American manufacturer of transport temperature control systems for refrigerator trucks and trailers, refrigerated containers and refrigerated railway cars along with heating, ventilation and air conditioning systems for bus and ...

with entrepreneur Joseph A. "Joe" Numero. In 1938 Numero sold his Cinema Supplies Inc. movie sound equipment business to

RCA The RCA Corporation was a major American electronics company, which was founded as the Radio Corporation of America in 1919. It was initially a patent trust owned by General Electric (GE), Westinghouse, AT&T Corporation and United Fruit Comp ...

to form the new entity, U.S. Thermo Control Company (later the

Thermo King Corporation Thermo King is an American manufacturer of transport temperature control systems for refrigerator trucks and trailers, refrigerated containers and refrigerated railway cars along with heating, ventilation and air conditioning systems for bus and ...

), in partnership with Jones, his engineer. Jones designed a portable air-cooling unit for trucks carrying perishable food, for which they obtained a patent on 12 July 1940, 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, 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 The COVID-19 pandemic, also known as the coronavirus pandemic, is an ongoing global pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The novel virus was first identi ...

and its associated vaccinations, have caused vastly increased need.

Uses

Cold chains are common in the food and

pharmaceutical A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy ( pharmacotherapy) is an important part of the medical field and ...

industries and also in some chemical shipments. One common temperature range for a cold chain in pharmaceutical industries is , but the specific temperature (and time at temperature) tolerances depend on the actual product being shipped.

Produce

Unique to fresh produce cargoes, the cold chain requires to additionally maintain product specific environment parameters which include air quality levels (carbon dioxide, oxygen, humidity and others).

Vaccines

The cold chain is used in the supply of

vaccines A vaccine is a biological preparation that provides active acquired immunity to a particular infectious or malignant disease. The safety and effectiveness of vaccines has been widely studied and verified.

to distant clinics in hot climates served by poorly developed transport networks. Vaccines can lose their efficacy if cold chain management fails. Disruption of a cold chain due to war may produce consequences similar to the

smallpox Smallpox was an infectious disease caused by variola virus (often called smallpox virus) which belongs to the genus Orthopoxvirus. The last naturally occurring case was diagnosed in October 1977, and the World Health Organization (WHO) c ...

outbreaks in the Philippines during the

Spanish–American War , partof = the Philippine Revolution, the decolonization of the Americas, and the Cuban War of Independence , image = Collage infobox for Spanish-American War.jpg , image_size = 300px , caption = (clock ...

, during which the distributed vaccines were inert due to lack of temperature control in transport. 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, such as those for chickens. 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. In 2020, during the

, vaccines being developed may need ultracold storage and transportation temperatures as cold as , requiring what has been referred to as a "colder chain" infrastructure. 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.

Validation

Sunwell fish packing pumpable slurry ice

The cold chain distribution process is an extension of the

good manufacturing practice Current good manufacturing practices (cGMP) are those conforming to the guidelines recommended by relevant agencies. Those agencies control the authorization and licensing of the manufacture and sale of food and beverages, cosmetics, pharmaceut ...

(GMP) environment that all drugs and biological products are required to follow, and are enforced by the various health regulatory bodies. As such, the distribution process must be validated to ensure that there is no negative impact to the safety, efficacy or quality of the drug substance. The GMP environment requires that all processes that might impact the safety, efficacy or quality of the drug substance must be validated, including storage and distribution of the drug substance. A cold chain can be managed by a

quality management system A quality management system (QMS) is a collection of business processes focused on consistently meeting customer requirements and enhancing their satisfaction. It is aligned with an organization's purpose and strategic direction (ISO 9001:2015). I ...

. Temperature data loggers and

RFID Radio-frequency identification (RFID) uses electromagnetic fields to automatically identify and track tags attached to objects. An RFID system consists of a tiny radio transponder, a radio receiver and transmitter. When triggered by an electromag ...

tags help monitor the temperature history of the truck, reefer container, warehouse, etc. and the temperature history of the product being shipped. They also can help determine the remaining

. Also, temperature sensors may need to be

National Institute of Standards and Technology The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into physical s ...

(NIST) traceable depending on the body monitoring the cold chain.

History

Uses

Produce

Vaccines

Validation

See also

Sources

References

Further reading