Cold chain

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The cold chain is the continuous system of cooling during transport between manufacturer, wholesaler, dealer and consumer; especially of food and increasingly also of medical or chemical products.

Market requirements

The number of products requiring refrigeration is increasing significantly. In addition to pharmaceutical and cosmetic products, this mainly applies to fresh and frozen foods. The logistics industry uses a large number of special containers and vehicles to deliver goods to recipients in the freshest possible condition. GPS-supported fleet management systems are also increasingly being used here , which permanently record the cooling temperature and send it cyclically to a control center in order to check compliance with the cooling chain and to be able to react promptly.

The 360 Quality Association, for example, aims to maintain, improve and document the quality standard in the cold chain.

The Cold Chain Management ( English cold chain management ) deals with the efficient control and the organization of production and logistics relating to the cold chain.


Fresh and frozen goods , the shelf life of which depends on constant refrigeration, require uninterrupted refrigeration in order to protect them from spoilage for as long as possible. The legal regulations for frozen meat and fresh meat regulate the temperature zones for the cold chain of various foods: Frozen meat and frozen fish must be permanently and consistently cooled to minus 18 degrees Celsius. A maximum temperature of 4 degrees must be guaranteed for fresh meat, and 8 degrees for milk and dairy products. Chocolate needs temperatures of 15 to 18 degrees. Different temperatures must be ensured for fruit and vegetables depending on the type. For example, fresh apples are transported at 1 to 4 degrees, mangoes at around 12 degrees Celsius. There are correspondingly complex requirements for the logistics of food . Refrigerated vehicles therefore often have several cooling chambers with different temperature zones.

If there is a break in the cold chain, food may be spoiled, its quality reduced or its shelf life impaired. Such foods are usually taken off the market and destroyed. If, however, food that has been affected in this way is put on the market, it is not insignificantly reduced in its value, in particular in its nutritional or enjoyable value or in its usefulness. This deviation from the public opinion must be made sufficiently clear, otherwise there is a legal violation sanctioned by the LFGB .

Medical products

Medical products are often sensitive to temperature fluctuations. The lifespan of vaccines, for example, can be significantly shortened if a certain storage temperature is exceeded or not reached even for a short time. If, in certain cases , there is no exact proof of the temperature during transport , a fluctuation must be assumed and the product must be destroyed. The same applies to blood products , infusions , bacterial cultures , chemical reagents and certain pharmaceuticals used in human and veterinary medicine .

In general, cold chains are divided into active and passive cold chains. Medicines that require cooling can be cooled actively as well as passively. Cold chain drugs are handled differently. These must not be passively cooled. In the case of drugs that are subject to cold chain requirements, it must always be ensured that the cooling is continuous and uninterrupted.

Active cold chain

The aim of the active cold chain is to keep the prescribed and defined temperature intervals for drugs at all times. In addition to continuous cooling, continuous temperature control and recording is also carried out. Due to the temperature sensitivity of cold chain drugs, the handling of these products and goods has the highest priority. Vehicles that are used for the transport of medicinal products that are subject to cold chain requirements must be qualified before use and equipped with suitable temperature control systems (loggers); the same applies to storage areas.

Passive cold chain

In addition to active cooling, there is the option of passively cooling drugs. However, passive cooling is only used as an intermediate stage between active cooling, mostly when transporting between wholesalers and pharmacies. The vehicles are not equipped with cooling technology. In order to maintain the temperature intervals, suitable insulation techniques are used during transport. Depending on the geographical location in which the transports are carried out, transports with passive cooling can be carried out all year round, seasonally or only occasionally. Added to this are the duration of the transports and the interior insulation of the transporters themselves. Due to the high costs of actively cooled transports, transport service providers and wholesalers often decide whether passive transports are possible depending on the day and the weather. For this purpose, when making a decision, use is made of data that was collected as part of temperature monitoring. The decision whether transports are actively or passively cooled is also based on the insulation of the drug packaging itself. In addition to the informative use of the packaging, it must also withstand physical, biological, climatic and chemical loads.

The legislation specifies regulations for the transport and storage of refrigerated and cold chain pharmaceuticals. In particular, the GMP guideline for manufacturers specifies how pharmaceuticals must be produced and handled in order not to have a lasting effect on quality. Quality control is therefore an important part of storage, production and transport and must be adequately documented and carried out by all those involved in the supply chain.

In addition, since November 1, 2006, the Ordinance on the Manufacture of Drugs and Drugs (AMWHV) has been in effect. This stipulates that starting materials, intermediate and end products are not damaged by storage and transport on the way to the customer. The EU is also planning a regulation for the complete documentation of the transport route of such products. Conventional solutions usually special packaging in combination with passive cooling by dry ice , often not enough here longer.

Chemical products

Chemical semi-finished products are often subject to requirements for certain storage and transport temperatures and times, as otherwise they will already react or lose specified properties. Molding compounds ( thermosets ) for the production of housings for ICs are an example of this.

Technical systems for temperature control

  • Fresh Check is an indicator from the US company Temptime. A polymer is put together and applied, which, depending on time and ambient temperature, is linked and leads to an increasingly darker color.
  • The blue dot from BASF and its Israeli partner Freshpoint is a label that is attached directly to the food packaging line and activated with UV light . The dye on the so-called OnVu label fades faster the higher the temperature. OnVu is already used by several customers in Europe and North America.
  • The US company 3M works with its indicator with the melting point of a colored wax, which is covered with a permeable protective layer. If the wax melts at a given temperature, it penetrates to the outside and then solidifies clearly visible on the surface.
  • The CheckPoint label from the Swedish manufacturer Vitsab works with the temperature-dependent reactions of enzymes that cause a color change.
  • The PolyTakSys plastic chip developed by the University of Münster (Prof. Dr. Meinhard Knoll) uses organic electronics to measure the time since the food was packed , taking the ambient temperature into account. Depending on the process, the remaining time changes, which is displayed optically and can also be transmitted to the cash register system by radio.

Radio frequency identification (RFID) as a documentation tool

Logistics companies developed special industry solutions for the food , health and cosmetics industries in order to be able to offer reliable temperature-controlled transport. Radio frequency identification (RFID) is developing into a key technology in this area , because it guarantees quality even where conventional systems reach their limits. With some logistics companies, products that require refrigeration can be transported in a temperature zone between 2 and 8 degrees Celsius. The temperature is measured, monitored and seamlessly documented over the entire transport route. Upon request, each individual package can be equipped with a reusable RFID chip that measures the temperature of the goods exactly.

The RFID system consists of two components, the reader / writer and the transponder , also known as a tag . The reader acts as an interface between software and the data memory on the transponder, in which the information is stored and from which it can be called up. The transponders equipped with a temperature sensor can record the course of the ambient temperature in their memory. The data can then be read out via the reader and transmitted to a computer . If a reader sends a radio signal , the nearby transponder responds and the information stored in it is transferred to the software via the reader.

Since neither physical nor optical contact is necessary for communication , the data can also be read from transponders inside packaging , for example . Under certain circumstances, the mostly insulating packaging material can cause problems with recognizing and reading the transponder. In addition, the readers can rewrite the data carriers. During such write processes, the read / write device establishes communication with the transponder and forwards the information from the respective application to the transponder, for example to reprogram it or to program it differently or to add data. The stored temperature data are, however, tamper-proof and therefore cannot be changed.

Monitoring during transport

Most manufacturers of cooling units offer so-called temperature data recorders ( cooling data loggers ) for monitoring the cold chain in transport . These contain a data memory and usually a printer for printing out the temperature profile, which can be used as proof of delivery to the customer. These devices report (optically and / or acoustically) malfunctions of the system or alarms when the specified temperatures are exceeded.

In areas where redundant monitoring independent of the actual cooling system is necessary, manufacturer-independent systems with separately installed temperature sensors are used.

In both cases, these operating states, temperature data and curves can be transmitted and recorded online in real time. To this end, various companies offer systems that connect the cooling system with internet portals for monitoring the cooling in the vehicles. Large haulage companies are also happy to integrate these subsystems into their fleet management solutions. This means that you are independent of manufacturer portals and can link the recorded temperature data directly with other operating processes.

Individual evidence

  1. Stoller, CW (Ed.): Pharmalogistik . 2017.
  2. Meinhard Knoll: Website of the research project PolyTakSys
  3. TKDL
  4. Euroscan: X2 Temperature recorder
  5. Seven Telematics: Temperature Recorders

Web links