Compiled by Eamonn Ryan
The following presentation was delivered at the 2024 Cold Chain Refrigeration, Logistics and Technology Summit in Cape Town, by University of Stellenbosch researcher Dr Tarl Berry, on the topic ‘Cold chain logistics and the drive for resilience in Africa’s food chain’, in collaboration with Citrus Research International.
The citrus supply chain faces challenges in maintaining market access, quality control, and cost-effectiveness. There’s a need for efficient temperature and humidity control, more depots and cold storage facilities, and optimised airflow and temperature fluctuations to reduce spoilage and improve fruit quality. In optimising fresh produce supply chain management, Berry emphasises the importance of understanding shelf life, using data-driven decision-making, and leveraging digital twins to optimise supply chain processes.
“The citrus supply chain comprises several critical stages, each presenting unique challenges and opportunities. From cultivation on diverse farms across varying environmental conditions to meticulous packing and handling in cold storage facilities, the journey of citrus fruits involves multiple exposures to environmental factors and logistical challenges.”
Berry highlights the significance of inland transportation, often spanning vast distances from farms in countries like Botswana and Zimbabwe to major ports. The quality of roads and infrastructure plays a crucial role in preserving the freshness and quality of citrus during this journey.
As the second largest exporter of citrus in the world, the South African citrus industry faces the dual challenge of expanding market reach while maintaining stringent quality standards. Berry notes the diverse geographic spread of production across 20 distinct regions, each with its own environmental conditions and logistical considerations.
“Market dynamics are constantly evolving, with traditional markets like Europe showing reduced demand while emerging markets in the Middle East and China present new opportunities. The shift in market preferences underscores the need for agile logistics and strategic planning to ensure timely delivery and competitive pricing.”
Berry emphasises the time-sensitive nature of citrus transportation, where even minor delays can impact fruit quality and marketability. The average transit times to various global destinations vary significantly, reflecting the logistical complexities involved in maintaining freshness over long distances. In response to these challenges, industry experts advocate for strategic enhancements across the citrus supply chain:
Implementing precise temperature and humidity control measures at every stage—from farm to market—is crucial for preserving fruit quality and extending shelf life.
Enhancing airflow and minimising temperature fluctuations in storage and transportation facilities can significantly reduce spoilage and ensure consistent product quality.
Leveraging data analytics and digital twin technologies enables real-time monitoring and predictive insights, empowering stakeholders to make informed decisions that optimise supply chain efficiency and responsiveness.
“Unlike some fruits, citrus exhibit linear respiration rates, necessitating meticulous control of temperature and environmental conditions throughout their journey. Factors like resource depletion post-harvest and the risk of chilling injury during transport pose significant challenges that must be managed while maintaining cost-effectiveness.”
A key concern in global citrus trade is compliance with international phytosanitary regulations – measures which focus on preventing, controlling and mitigating the introduction, spread and establishment of quarantine pests of plants, particularly concerning pest control. Different countries impose varied requirements for pest treatments, such as cold treatments or chemical interventions, to prevent the spread of pests like fruit flies. Berry highlights the logistical complexity of managing these treatments effectively, often opting for treatments onboard shipping vessels to minimise transit time and maximise freshness.
“Temperature management is critical in preserving citrus quality during transit. An intricate balance is required to maintain optimal temperatures that both inhibit pests and preserve fruit quality without inducing chilling injury.” He presents data illustrating this delicate balance, emphasising the need for precise temperature control technologies and methodologies.
Innovations in containerisation and airflow control
Berry delves into innovative solutions aimed at enhancing airflow uniformity within shipping containers. Technologies like the ‘void block’ and newly developed ‘floaty’ improve airflow distribution, reducing temperature differentials within containers. These advancements not only optimise fruit quality but also streamline logistics, ensuring consistent product performance across varying environmental conditions.
“Innovative packaging solutions play a crucial role in maintaining fruit integrity and minimising damage during transit. Novel measurement techniques borrowed from other industries, such as resistance testing, provide valuable insights into airflow dynamics within packaging, optimising fruit preservation strategies.”
Berry encourages expanded infrastructure, including more depots and cold storage facilities, to accommodate growing citrus production and facilitate efficient global distribution. Collaborative efforts across the industry, including research institutions, governmental bodies, and private enterprises, are crucial in driving innovations that address current challenges and pave the way for a more resilient and sustainable citrus supply chain.
There are challenges associated with implementing new container designs within the industry. Despite the proven benefits of improved airflow, integrating these innovations requires overcoming technical hurdles and addressing concerns around logistical compatibility and operational changes. In addition to physical innovations, Berry introduces a data-driven approach to optimise container cooling processes. By leveraging big data analytics, Berry and his team analyse temperature variations within containers and correlate these findings with fruit quality outcomes. This approach not only enhances predictive capabilities but also informs strategic decisions to mitigate risks and improve overall supply chain efficiency.
Reflecting on his experiences, Berry discusses unexpected challenges encountered during implementation, such as unforeseen impacts on production machinery due to minor design modifications. This highlights the importance of rigorous testing and collaboration across multiple stakeholders to preemptively address potential issues and ensure seamless integration of new technologies.
Berry introduces the concept of digital twins, which replicate real-world processes within a virtual environment. For each shipment, a digital twin provides a comprehensive view of temperature variations, moisture loss (transpiration), and other critical factors impacting fruit quality. By integrating data from sensors and historical climate records, the Stellenbosch University team simulates environmental conditions to predict shelf-life degradation and identify optimal shipping strategies.
Using 2021 data, Berry demonstrated to the Summit how digital twin simulations analyse every pallet’s journey through the supply chain. This simulation captures the dynamic interplay between packaging types, fruit varieties, and storage conditions. For instance, oranges exhibit varying shelf-life capacities based on temperature fluctuations during transit. Insights gleaned from these simulations highlight critical points where quality deterioration occurs, empowering stakeholders to implement targeted interventions.
There is an inherent variability in fruit quality across different stages of the supply chain. From initial cold storage to containerised shipping and retail distribution, maintaining consistent quality poses significant challenges. Soft-skin varieties are prone to accelerated quality decline, with some shipments arriving at retail with minimal viable shelf life. These findings point to the need for precise temperature management and packaging strategies to mitigate quality loss effectively.
Berry’s research represents a paradigm shift in citrus supply chain logistics, driven by technological advancements and empirical insights. By harnessing digital twins and advanced analytics, stakeholders can navigate complexities, minimize waste, and uphold stringent quality standards.