The term cold chain or cool chain denotes the series
of actions and equipment applied to maintain a product within a specified
low-temperature range from harvest/production to consumption.A cold chain is
a temperature-controlled supply chain.
An unbroken cold chain is an uninterrupted series of refrigerated production,
storage and distribution activities, along with associated equipment and
logistics, which maintain a desired low-temperature range. It is used to
preserve and to extend and ensure the shelf life of
products, such as fresh agricultural produce, seafood, frozen food, photographic
film, chemicals, and pharmaceutical
products.Such products, during transport and 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.
Cold chain logistics includes all of the means used to ensure a constant temperature for a product that is not heat stable, from the time it is manufactured until the time it is used. Moreover, cold chain is considered as a science, a technology and a process. It is a science as it requires the understanding of the chemical and biological processes associated with product perishability. It is a technology as it relies on physical means to ensure desirable temperature conditions along the supply chain. It is a process as a series of tasks must be performed to manufacture, store, transport and monitor temperature sensitive products.
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 2 to 8 °C (36 to 46 °F), but the specific
temperature (and time at temperature) tolerances depend on the actual product
being shipped. 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), which
makes this the most complicated cold chain to operate.
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.
There have been numerous events where vaccines have been shipped to third world countries with little to no cold chain infrastructure (Sub-Sahara Africa) where the vaccines were inactivated due to excess exposure to heat.[citation needed] Patients that thought they were being immunized, in reality were put at greater risk due to the inactivated vaccines they received. Thus great attention is now being paid to the entire cold chain distribution process to ensure that simple diseases can eventually be eradicated from society.
Traditionally all historical stability data developed for vaccines was based on the temperature range of 2–8 °C (36–46 °F). With recent development of biological products by former vaccine developers, biologics has fallen into the same category of storage at 2–8 °C (36–46 °F) due to the nature of the products and the lack of testing these products at wider storage conditions.
The cold chain distribution process is an extension of the good manufacturing practice (GMP) environment that all drugs and biological products are required to adhere to, 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.
Cold chain logistics market is segmented into type, temperature type, application, and region. Based on application, cold chain logistics market is segmented into dairy & frozen desserts, meat, fish & seafood, fruits & vegetables, bakery & confectionery. Dairy & frozen desserts are estimated to hold largest share of cold chain logistics market due to need of maintaining constant temperature.
The report study has analyzed revenue impact of covid-19 pandemic on the sales revenue of market leaders, market followers and disrupters in the report.
Rising variety of frozen products such as ice-cream, meat, and seafood are stored at freezing temperature will boost the cold chain logistics market. Increasing international trade of perishable processed food will lead the cold chain logistics market. Growing focus toward improvement of storage is booming the cold chain logistics market.
Being able to ensure that a shipment will remain
within a temperature range for an extended period of time comes down largely to
the type of container that is used and the refrigeration method. About 20% of
all the energy consumed in cold chain logistics involves cargo refrigeration.
Factors such as duration of transit, the size of the shipment and the ambient
or outside temperatures experienced are important in deciding what type of
packaging is required and the related level of energy consumption. They can range
from small insulated boxes that require dry ice or gel packs, rolling
containers, to a 53 footer reefer which has its own powered refrigeration unit.
The major cold chain technologies in providing a temperature-controlled
environment during transport involve:
- Dry ice. Solid carbon dioxide, is about -80°C and is capable of keeping a shipment frozen for an extended period of time. It is particularly used for the shipping of pharmaceuticals, dangerous goods, and foodstuffs and in refrigerated unit load devices for air cargo. Dry ice does not melt, instead, it sublimates when it comes in contact with air.
- Gel packs. Large shares of pharmaceutical and medicinal shipments are classified as chilled products, which means they must be stored in a temperature range between 2 and 8°C. The common method to provide this temperature is to use gel packs, or packages that contain phase changing substances that can go from solid to liquid and vice versa to control an environment. Depending on the shipping requirements, these packs can either start off in a frozen or refrigerated state. Along the transit process, they melt to liquids, while at the same time capturing escaping energy and maintaining an internal temperature.
- Eutectic plates. Also known as “cold plates”. The principle is similar to gel packs. Instead, plates are filled with a liquid and can be reused many times. Eutectic plates have a wide range of applications, such as maintaining cold temperatures for rolling refrigerated units. They can also be used in delivery vehicles to keep the temperature constant for short periods of time, a process that can be suitable for deliveries in noise-sensitive areas or for night deliveries.
- Liquid nitrogen. An especially cold substance, of about -196°C, used to keep packages frozen over a long period of time. Mainly used to transport biological cargo such as tissues and organs. It is considered as a hazardous substance for the purpose of transportation.
- Quilts. Insulated pieces that are placed over or around freight to act as a buffer in temperature variations and to maintain the temperature relatively constant. Thus, frozen freight will remain frozen for a longer time period, often long enough not to justify the usage of more expensive refrigeration devices. Quilts can also be used to keep temperature-sensitive freight at room temperature while outside conditions can substantially vary (e.g. during the summer or the winter).
- Reefers. The generic name for a temperature-controlled transport unit, which can be a van, small truck, a semi-trailer, or a standard ISO container. These units, which are insulated, are specially designed to allow temperature-controlled air circulation maintained by an attached and independent refrigeration plant. A reefer is, therefore, able to keep the cargo temperature cool and even warm. The term reefer increasingly applies to refrigerated forty-foot ISO containers with the dominant size being 40 high-cube footers (45R1 being the size and type code).
The cold storage facility is the most commonly used
in cold chain logistics. It can range from a single temperature-controlled room
servicing a single user and function to a large dedicated distribution center servicing
multiple users and functions. There are also punctual examples such as converting mines into
cold storage facilities.
Cold
Chains Operations
Moving a shipment across the supply chain without
suffering any setbacks or temperature anomalies requires the establishment of a
comprehensive logistical process to maintain the shipment integrity. This
process concerns several phases ranging from the preparation of the shipments
to final verification of the integrity of the shipment at the delivery point:
- Shipment preparation. When a temperature-sensitive product is being moved, it is vital to first assess its characteristics. A key issue concerns the temperature conditioning and the packaging of the shipment, which should already be at the desired temperature. Cold chain devices are commonly designed to keep the temperature constant, but not to bring a shipment to this temperature, so they would be unable to perform adequately if a shipment is not prepared and conditioned. A notable exception concerns bananas which are transported around a temperature of 13o Celsius, for which it is possible to use a reefer to cool down the shipment. Other concerns include the destination of the shipment and the weather conditions for those regions, such as if the shipment will be exposed to extreme cold or heat along the transport route. Using a reefer with its own power unit usually mitigates such concerns. The load unit carrying the temperature-sensitive cargo must also be prepared. For instance, a refrigerated container must be steam cleaned to remove the risk of bacterial contamination and brought to the specified conditions of the shipper, namely temperature and humidity. Another issue concerns atmospheric control, which is maintaining appropriate oxygen and carbon dioxide levels, helping control (delay) the ripening. This control can apply to the whole conveyance (reefer) but commonly involves wrapping products in polyethylene bags, which controls how gases permeate during transport.
- Modal choice. Several key factors play into how the shipment will be moved. Distance between the origin and the final destination (which often includes a set of intermediary locations), the size and weight of the shipment, the required exterior temperature environment, and any time restrictions (perishability) of the product all affect the available transportation options. Short distances can be handled with a van or a truck, while a longer trip may require an airplane or a container ship. In this case, the cost/perishability ratio becomes a factor in the modal choice.
- Custom procedures. If the freight crosses boundaries, custom procedures can become very important, since cold chain products tend to be time-sensitive and more subject to inspection than regular freight (e.g. produce, pharmaceuticals, and biological samples). The difficulty of this task differs depending on the nation (or economic bloc) and the gateway since there are variations in procedures and delays. A common issue relates to sanitary inspection that may require fumigation. Customs issues are commonly identified as the most crucial in establishing reliable international cold chains.
- The “Last Mile”. The last stage is the actual delivery of the shipment to its destination, which in logistics is often known as the “last mile”. Key considerations when arranging a final delivery concern not only the destination but the timing of the delivery so the critical labor and warehousing space is available. Trucks and vans, the primary modes of transportation for this stage, must meet the specifications necessary to transfer the cold chain shipment. Since many deliveries of cold chain products, particularly groceries, are taking place in an urban setting, they are impeded by congestion and parking difficulties Also important is the final transfer of the shipment into the cold storage facilities as there is potential for a breach of integrity and damages to fragile goods such as produce.
- Integrity and quality assurance. After the shipment has been delivered, and temperature recording devices or known temperature anomalies must be recorded and made known. This is the step of the logistical process that creates trust and accountability, particularly if liability for a damaged shipment is incurred. If problems or anomalies that compromise a shipment do occur, an effort must be made to identify the source and find corrective actions. This is particularly relevant to the high value of cold chain goods. While a standard container load can have a value between $50,000 and $100,000, a reefer load can reach $1 million. For the case of pharmaceuticals, the value of the cargo can reach $50 million.
Therefore, the setting and operation of cold chains
are dependent on the concerned supply chains since each cargo unit to be
carried has different requirements in terms of location, demand, level of
concentration, load integrity, and transport integrity. Because of the
additional tasks involved as well as the energy required for the refrigeration
unit transportation costs for cold chain products is much higher than regular
goods. The ongoing rise in standards of living and economic specialization will
remain important drivers for years to come in the growing demand for perishable
goods and the cold chain logistics supporting their transport.
0 Comments