COLD CHAIN LOGISTICS

Cold Chain Logistics (CCL) of fresh agricultural products refers to the food supply logistics chain that uses refrigeration technology to continuously maintain a suitable temperature and humidity environment for perishable products such as fruits, vegetables, dairy, meats, and Fish.

An integral and efficient cold chain system must maintain perishable food within the desired temperature and humidity range from the collection point (be it harvest, slaughter, or fishing) to the point of final consumption. Any breaks in this chain (i.e., excursions in temperature or/and humidity beyond the desired ranges) render the entire cold chain useless. Therefore, maintaining CCL integrity is crucial to reduce food loss and waste, and this requires the coordinated development of the various links in the CCL and data sharing and transparency between the relevant enterprises and stakeholders.

In addition, ensuring a suitable humidity environment for foodstuffs is important for reducing water loss and maintaining the sensory quality of fresh agro-products, which directly affects consumer buying decisions, market prices, and sales volume – and thus affects the overall economics of the food industry.  Inappropriate humidity is not conducive to maintaining the quality and safety of fresh foods; for example, low humidity not only increases moisture loss and accelerates the deterioration of sensory quality (e.g., pigments, colours, and texture) but also reduces the thawing efficiency for frozen foods. High humidity promotes the growth of bacteria, thereby enhancing the incidence of disease and decay, especially for meat products. Perishable products need robust cold chain packaging with good protection properties as well as the ability to prevent or alleviate temperature disruptions during transportation and storage.

Given the constant interaction between fresh food and the environment, breaks in the cold chain may accelerate the rate of food spoilage and even make subsequent application of the cold chain irrelevant. In recent years, to maintain cold chain integrity and accurately monitor the low-temperature environment and food quality, automated monitoring systems have been developed to collect the ambient conditions and other parameters of the cold chain of fresh produce (e.g., location, illumination conditions, concentration of heavy metals) by using IoT technology such as RFID, WSNs, near-field communication, and compressed sensing technology. This technology allows for real-time monitoring of food safety and quality, reduces the risk of undetected breaks in the cold chain, and improves the precision and logistical decision making (e.g., route optimization, shelf-life prediction, and energy optimization).

Temperature abuses result in variations of product quality during distribution and at the end of shelf life and may cause spoilage before the use by date is reached, leading to food waste and economical losses. The vulnerability of cold chain became very important in modern, global trade where distribution chain is sometimes very complex and long (slaughterhouse-transportation/distribution retail-consumer continuum), where it has to be shipped from one to another country or from one to another continent (Figure 1). Therefore, the management of cold chain is of paramount importance and presents a permanent challenge to maintain the safety and freshness of chilled fresh agro products until it reaches the final consumer.

Stages of the cold chain

Pre-cooling, warehouse refrigeration, refrigerated transport, and marketing are four commercial CCL links, and the main responsibility for food safety is held by Food Business Operator (FBOs). Although a self-inspection system and hazard analysis and critical control can be applied to FBOs, it may be inevitable that most food loss occurs in these stages. Fortunately, this phenomenon results in relatively little food waste and environmental effects because the food can be used for animal feed. Once fresh food is purchased by the consumer, food safety mainly depends on their behaviour and domestic environment. Food is often wasted because it finds no alternative use at the household level, so severe food loss (or waste) and a high risk of food borne illness occur at this end of the CCL, even in developed countries, due to ignorance of good hygiene and refrigeration practices. However, most food loss and food borne illness that occur in households are avoidable through regular temperature verification, refrigeration disinfection, and improved household hygiene for food handling, preparation, and cooking.

Advances in information technology have significant potential for reducing the rate of food loss and food borne disease throughout the CCL, which is a major driving force promoting the intelligent and efficient development of the CCL. However, these technologies require further support and research from experts, countries, and industries, such as technology implementation, infrastructure configuration, data security, privacy protection, and robust legal frameworks.

Figure 2 shows the contribution of the various thermal loads to the overall energy consumption of refrigerated systems. Minimizing the energy consumption of refrigerated transport systems translates into minimizing the various thermal loads that are transferred into the refrigerated space. A VARS coupled with a Solid-Oxide Fuel Cell (SOFC) for large, medium, and small refrigerated trucks is a favourable alternative to conventional diesel-engine-driven VCRSs. The results show that the SOFC-coupled VARSs can refrigerate the cargo with negligible greenhouse-gas emissions compared with other refrigerated transportation technologies and zero emissions of particulate matter and NOx. Therefore, environmentally benign refrigerants and alternative refrigeration systems have the potential not only to reduce or even eliminate the problem of refrigerant leakage but also to significantly decrease the energy consumption.

Conclusion

The cold chain management in agro product supply is of utmost importance for the maintenance of quality and safety of agro products. The complexity of global supply chain, with frequently long distribution chains associated with transportation of the product within the country or from one to another country and from one to another continent, makes the solutions for the chilling and freezing regimes, as well as monitoring of time-temperature profiles, very important for the overall success in delivery of product which will be accepted by consumer for its freshness and safety levels.

Although the importance of chilling and freezing regime effectiveness and temperature monitoring along the cold supply chain are well known, it remains a permanent challenge for the industry, distributors, retailers and consumers.

Dr. (Prof.) D.B. Jani received Ph.D. in Thermal Science (Mechanical Engineering) from Indian Institute of Technology (IIT) Roorkee. Currently he is a recognized Ph.D. Supervisor at Gujarat Technological University (GTU). He has published more than 180 Research Articles in reputed International Conferences and Journals. He has also published 5 reputed books in the area of thermal engineering. Presently, he is an Associate Professor at GEC, Dahod, Gujarat Technological University, GTU, Ahmedabad (Education Department, State of Gujarat, India). His area of research is Desiccant cooling, ANN, TRNSYS, and Exergy.