Monitoring of temperature and ethylene conditions after harvest to improve outturn quality of Queensland lemons in export supply chains

Monitoring of temperature and ethylene conditions after harvest to improve outturn quality of Queensland lemons in export supply chains

26 February 2019

Managing temperatures after harvest is a key factor in ensuring appropriate and reliable quality for customers and consumers.

Over the last two seasons, the Serviced Supply Chains project team has worked with citrus grower and exporter Greg Parr (Glengrove Orchards), to monitor citrus lemon export consignments from Gayndah (central Queensland) to Jakarta (Indonesia).

Loggers were installed into fruit cartons prior to forced air cooling and loading into refrigerated sea containers.

Monitoring of temperatures from harvest to outturn in the export market was undertaken using the Radio Frequency Identifier (RFID) -based Xsense system (BT9 Ltd), the real time SIM-based SmartTraxxTM (Emerson Inc) and a range of conventional manual download (USB) loggers.

A summary of monitoring technologies, are available here.

Monitoring during the 2017 and 2018 seasons was used to document variations in ethylene and temperature conditions within lemon supply chains and to identify critical control points that are likely to influence outturn quality, especially skin damage likely related to chilling.

Four critical control points were identified during chain monitoring and investigated by laboratory trials:

1. The degreening process prior to packing and grading, where temperatures above 24°C and ethylene concentrations above 5 ppm increased the risk of skin damage after cold disinfestation.
2. The fruit consolidation period, where variations in time between packing (0 Days) and forced-air cooling during which fruit are stored at 7 degC (1-14 days), may provide a conditioning effect.
3. Forced air cooling prior to loading containers, where variations in conditions to bring all of the fruit down to the disinfestation protocol temperature may increase the risk of skin damage.
4. The in-transit disinfestation conditions from container loading to market destination, where temperatures below 2C can increase the risk of skin damage.

Based on this information, Greg has focussed on improving temperature and ethylene management during degreening and ensuring that fruit requiring multiple degreening events were not included in export shipments.

Greg has been working closely with DAF to collect temperature data, within the chain, (Figure 1 [below] is an example of temperatures on farm and during export), to analyse the monitoring data, and to conduct detailed experiments to verify where chain improvements can be made to more consistently deliver lemons that meet export customers’ expectations.

Further information on chain monitoring, including placement of loggers in export shipments is available here.

Article submitted by Andrew Mead, Noel Ainsworth, Yiru Chen and Andrew Macnish, of Department of Agriculture and Fisheries, Queensland. For more information, contact Andrew Mead via email andrew.mead@daf.qld.gov.au or on (07) 4326 1144.

Acknowledgements: The Serviced Supply Chains project is funded by the Hort Frontiers Asian Markets Fund, part of the Hort Frontiers strategic partnership initiative developed by Hort Innovation, with co-investment from the Department of Agriculture and Fisheries, Queensland (DAF), Department of Jobs, Precincts and Regions (Victoria), Manbulloo (citruses), Montague Fresh (summerfruit), Glen Grove (citrus), the Australian Government plus in-kind support from the University of Queensland and the Chinese Academy of Sciences.