Cold Link Africa September 2024 | Page 30

The following presentation was delivered at the 2023 GCCA Cold Chain Conference in Cape Town , by University of Stellenbosch ’ s Professor Leila Gerber , cold chain specialist at the department of logistics , on the topic ‘ A comparison of different technologies to improve temperature control in refrigerated containers ’.
TECHNICAL

A grapes case study comparing different technologies to improve temperature control in refrigerated containers Compiled by Eamonn Ryan

The following presentation was delivered at the 2023 GCCA Cold Chain Conference in Cape Town , by University of Stellenbosch ’ s Professor Leila Gerber , cold chain specialist at the department of logistics , on the topic ‘ A comparison of different technologies to improve temperature control in refrigerated containers ’.

This presentation was of the university ’ s latest research focused on the table grape industry — a sector that epitomises the challenges and opportunities in cold chain logistics . Table grapes , known for their sensitivity , require precise temperature management to maintain their quality over long distances and through varying environmental conditions . This research explores the findings and highlights innovative strategies for improving efficiency and product integrity in cold chain logistics .

“ Our research , conducted for the table grape industry , underscores the critical importance of maintaining the correct temperature . Table grapes , originating from production areas with peak temperatures ranging from 32 ° C to 39 ° C , are highly susceptible to quality degradation if not kept within strict temperature limits . Previous studies have indicated insufficient airflow in reefer containers , leads to suboptimal cooling and increased claims from overseas importers regarding the quality of grapes upon arrival ,” says Gerber .
“ In response to these challenges , we were approached by a major South African
table grape exporter to evaluate new airflow technologies designed to enhance the cooling efficiency within reefer containers . For our trials , we used six refrigerated containers , each transporting 20 pallets of table grapes from South Africa to the Port of Rotterdam in the Netherlands . Specifically , we tested two innovative solutions : the Airflo floor covering and the Reefer Airflow Technology ( RAFT ) kit . The Airflo covering is placed at the base of the container to improve airflow , while the RAFT kit alters airflow direction from vertical to horizontal .”
Gerber notes : “ Our study involved temperature trials in which we placed temperature monitoring devices inside six reefer containers — three shipments with two containers each fitted with either Airflo or RAFT technology , and one control container per shipment . We installed temperature sensors to measure both ambient and pulp temperatures inside the containers . These containers were tracked from South Africa to the Netherlands , monitoring temperature profiles throughout the journey . We aimed to determine whether these airflow technologies effectively maintained the temperature within the desired range and
consequently improved the quality of the grapes upon arrival .” She lists the key findings :
• Temperature profiles : The data revealed that containers equipped with either Airflo or RAFT technology maintained more consistent temperature profiles compared to the control containers . This consistency is crucial in preventing quality degradation .
• Temperature breaks : “ Our analysis showed that temperature breaks — instances where the temperature deviated from the ideal range — were less frequent and shorter in containers using the new airflow technologies . Containers with more frequent and prolonged temperature breaks correlated with poorer quality grapes .”
• Impact on quality : Both Airflo and RAFT technologies demonstrated improvements in maintaining grape quality . However , the RAFT kit , with its horizontal airflow mechanism , showed a slightly better performance in ensuring uniform cooling across the entire container .
© Cold Link Africa
Professor Leila Gerber , cold chain specialist at the department of logistics , University of Stellenbosch .
BEST PRACTICES FOR COLD CHAIN MANAGEMENT
“ Our research highlights several best practices essential for optimising cold chain logistics for sensitive fruits like table grapes :
“ It is imperative to pre-cool products to the correct temperature before loading them

30 www . coldlinkafrica . co . za COLD LINK AFRICA • September 2024