Reporting transit conditions for mango quality

While the optimum conditions of transporting and ripening mangoes is more or less known throughout the industry, the inability to monitor and report these conditions can threaten the quality of fruit as it moves through the supply chain. 

Testing systems to monitor and report transit conditions when mangoes reach their destination has been the focus of a study by the Queensland Department of Agriculture, Fisheries and Forestry (DAFF), in partnership with Harvest Fresh Fruits.

Dr Peter Hofman, Senior Principal Horticulturist at DAFF stressed the importance of controlling and monitoring temperature, carbon dioxide and ethylene during transit. 

“Transport is an essential link in the supply chain. If a mango is not ripened under the right conditions, the fruit can have poor skin colour, poor flavour, skin damage and disease. Not knowing what conditions mangoes are in during transit can be the difference between delivering premium fruit and grade 2,” he said. 

A number of temperature monitoring systems have been available in the past, but with the growth of new technology, more accurate and cost effective systems have become available. 

“We hope that our research will identify an effective monitoring system that will record the conditions in a transport container, automatically report on them when the fruit arrives at its destination, and then give recommendations on further actions to produce the best quality fruit,” Dr Hofman said. 

Automatic identification (Auto-ID) or automatic data capture technologies, gather information on food commodities through the supply chain. Of the Auto-ID systems available, radio frequency identification (RFID) technology has developed into a quick and reliable system for identifying and tracking produce. 

RFID-based systems can use tags containing sensors for conditions such as temperature that can be placed in pallets at the farm. They can then monitor the conditions as the pallets move through the supply chain. When the pallet and tag is unloaded at the ripening centre, the data can be remotely downloaded to the internet via a reader, immediately producing a report of conditions during transport. Costs are as low as about $14 for the temperature tags and $1000 for the readers. 

“These technologies allow the quick and efficient transfer of information about the fruit conditions as they travel from farm to market. There is even the possibility of having alerts sent via email or text if the conditions during transport exceeds certain limits, and notification of when the pallets arrive at their destination. Using these technologies, producers and suppliers can better maintain the quality of fruit and provide healthy, fresh and quality products to customers,” Dr Hofman said. 

Currently, commercially available RFID technology can only report on temperature conditions. However the study aims to test RFID-based carbon dioxide and ethylene monitoring systems when they become available. 

This study is also looking at the optimum conditions for mango quality during transit. 

“Temperature is critical to delivering a quality mango, and the longer a mango is off the tree, the more important it becomes. Mango transport requires a specific temperature range that is low enough to reduce the rate of respiration to delay ripening, but not too low that chilling damage is caused to the fruit,” Dr Hofman said. 

Mangoes respire or breathe after harvest, and respiration happens at a quicker rate in warmer temperatures, causing the fruit to ripen and deteriorate faster. 

“As mangoes respire, they produce carbon dioxide, and when there is restricted ventilation, carbon dioxide concentrations can increase. We can get more green colour and disease in the fruit if they are ripened in concentrations of 3% carbon dioxide or above. In addition, concentrations above 3-4% is a significant worker safety issue. We found that ethylene concentrations should be maintained between 10-50 ppm during the first two to three days of ripening, and is of little benefit if applied later,” Dr Hofman said.

Project MG12016, In-transit ripening and prediction of outturn quality for mangoes, is funded by Horticulture Australia Ltd using voluntary contributions from Harvest Fresh Fruits and Mitsubishi Australia, and matched funds from the Australian Government. The Queensland Government through the Department of Agriculture, Fisheries and Forestry, and the University of Queensland, are co-funding this project.