Food cold chain: improving temperature control to reduce loss
Recent review articles provide an update on technologies to monitor temperature in the food cold chain, in order to avoid food loss during transport and retail.
Food losses due to improper temperature control
Based on various sources, the amount of food waste generated worldwide has been estimated between 931 million tonnes  to about 1.3 billion annually, representing 4.4 giga tonnes of CO2 emissions.  Most of the food waste is generated in households, but a significant amount of food loss occurs during transport and retail.
According to a recent review article, along the food chain, approximately 15% of food losses derive from transport, warehouse and retailing activities. The authors estimated that this represents about 200 million tonnes of food, equivalent to about 210 billion USD in losses.  Several studies indicate that temperature abuse is widely considered as one of the most important parameters decreasing the quality of perishable food and increasing economic losses.  Food loss is prevalent even in developed countries, where packaging and temperature management conditions are controlled. For example, a 2016 study in Spain showed that temperature abuse in retail refrigerated display cabinets was highly pronounced in the summer. As a result, remaining shelf life was reduced by 40%, 57% and 25% for smoked salmon, cooked chicken breast, and fresh cheese, respectively. 
Technologies to monitor temperature along the food cold chain
It is necessary to control and maintain the physical parameters (e.g., temperature, humidity) between the upper and the lower levels in trucks, aircrafts and ships. To date, wireless temperature-monitoring technologies, notably Radio Frequency Identification (RFID) tags and Wireless Sensor Networks (WSN), as well as Time-Temperature Integrators (TTIs), are probably the most widely employed systems used to measure, record, and monitor the temperature of products in the food cold chain.  Lately, the use of TTI technology has been declining because the information it provides is bound to the sensor. Newer solutions using IoT (Internet of Things) devices equipped with 3-5G technology offer the possibility to retrieve and process a large amount of data. Furthermore, the integration with GPS further expands the capabilities of devices in transport processes. 
Following the reviews of technologies used to maintain and control temperature in the food cold chain, researchers recommend the use of a technical system, comprised of RFID Data Loggers and sensors detecting specified parameters in real time, a wireless sensor network and cloud computing, and augmenting this system with methods of Statistical process control (SPC).
For example, in the case of a refrigerated truck, food warehouse or a supermarket, temperature measurements can be recorded in cargo space, refrigerators, deep freezers and on shelves at timed intervals on NFC Data Loggers. Data from each of these devices can be periodically stored in the cloud and later analysed using SPC. Results of those measurements and their analysis can be displayed on the smartphone of the driver or a warehouse clerk, triggering an alert and forcing corrective action. 
Food carriers using modern temperature recording tools usually react to an alarm signal, but they rarely analyse the causes. Unfortunately, scientific literature offering viable solutions are scarce. Furthermore, the solutions are sometimes either complicated or resource-intensive (manpower, time, costs, skilled technicians), hence their limited applicability. Training is needed to increase familiarity with statistical process control tools in transportation activity.
For more information on temperature fluctuation and abuse in the food cold chain, a review article was published in Foods.
 European Commission. Food waste. https://ec.europa.eu/food/safety/food-waste_en
 Skawińska, E.; Zalewski, R. Economic Impact of Temperature Control during Food Transportation - A COVID-19 Perspective. Foods 2022, 11(3), 467; https://doi.org/10.3390/foods11030467
 Ndraha, N., Hsiao, H. I., Vlajic, J., Yang, M. F., & Lin, H. T. V. (2018). Time-temperature abuse in the food cold chain: Review of issues, challenges, and recommendations. Food Control, 89, 12-21. https://doi.org/10.1016/j.foodcont.2018.01.027