Project on Pome, stone and grapes


Malcolm Dodd (Assciate Professor – Project leader) and Lynne Hoffman (HOD, Horticultural Science – Programme leader)


With the rapid adoption of twelve-meter refrigerated containers in preference to specialised refrigerated vessels as the means of shipping deciduous fruit along with all the challenges associated with Cold Sterilisation treatments, there has been a need to try and improve the efficacy of what is a forty-year-old design. The existing containers are limited in their ability to maintain the fruit temperatures and relative humidity during a voyage. In addition the containers fail to effectively manage cold sterilisation treatment protocols. Reversed air flow technology changes the way in which the chilled and return air is channelled and managed within refrigerated shipping containers. The technology changes the direction of the chilled delivery air from vertical to horizontal. In addition, the return air is managed through a duct which limits the amount of short circuiting of the chilled air that can occur. To test the efficacy of this technology on grapes, pome and stone fruit pulp temperature management and quality on a simulated shipping scale, numerous trials comparing a standard container to one fitted with reversed air flow have been conducted. The pulp temperature of the various fruits was always closer to the set point when stored under the reversed airflow technology compared to the control. The relative humidity in the reversed airflow container was always either the same or higher than that in the standard container. In addition the technology had no negative impact on the fruit quality and in many cases the quality was better after a subsequent shelf life analysis. The technology affords the deciduous fruit industry an alternative way of managing the cold sterilisation procedure by using suitably equipped containers. The reversed air flow technology has been registered by Stellenbosch University’s Innovus office as a patent, (PCT/IB/001811).