Monitoring the cool chain

  • Use loggers to improve fruit quality and shelf life
  • Access the temperature data in 'real time' to make decisions or change strategies
  • Different types of temperature monitoring technologies


Research monitoring temperature in sea freight and air freight.

Monitoring temperature of stonefruit during export (air and sea freight)

Presentation from Stonefruit Research Roadshow August 2019: Observations from monitoring sea and airfreight.

Video transcript

This project is looking at exports to Asian markets and in particular we are looking at China. Well, we've been monitoring the cool chain for stonefruit from the pack house in Victoria to the export markets in China and also to some other countries, Singapore and Malaysia.

Well, the information that we're gathering from the temperature monitoring is feeding into these DAT models, the decision aid tools and we are testing different mature fruit at different temperatures to see what effect it has on shelf life and quality, and also on ripening. Different issues between sea freight and airfreight. Sea freight is a longer time at a lower temperature, which is is good. For airfreight, it's a higher temperature for a shorter time, but then you have a longer shelf life period in the export markets. The kill zone for stone fruit is between three degrees and eight degrees, and every time the temperature of the fruit goes up and down between this zone, it can affect the quality and the shelf life of the fruit. The stone fruit market opened up to China, two or three years ago, and for the quarantine treatment, it's a cold treatment for sea freight, roughly two degrees for three weeks. The fruit is in transit for between 24 to 29 days and this appears to be a lot longer than a lot of the exporters anticipated. Generally, the temperatures are very good, between zero and two degrees, but the issue is the length of time that it takes to get to the market. Well, generally, the shelf life of stone fruit is somewhere between two to three, maybe four weeks. So the longer the sea freight just means that there's less time for the fruit to be in market at the other end. So the quality won't be as good.

The importers are requesting the growers to harvest fruit at six to eight kilograms of firmness, and it's a little immature, but it helps to withstand the long transit times of the sea freight. The main impact of harvesting stone fruit at high firmness is that some fruit may not ripen to its full potential, and that way the consumer is not experiencing the best quality fruit.

Well, we are monitoring the air freight for stone fruit to China and to Singapore and Malaysia. There is a methyl bromide treatment of a set rate, 18 grams per cubic metre for a set time, five and a half hours, and that's to satisfy the Chinese quarantine procedures. The main issue with air freight is probably higher temperatures, but only for a short time, maybe up to 10, 11, 12 degrees, but it is only for a short time.

Remote data loggers for fruit being exported

There are many types of temperature data loggers available to industry for remote monitoring of fruit along the export chain. Each type of temperature logger has its own merits ranging from:

  • ease of use,
  • cost,
  • accuracy,
  • reliability,
  • single use or reusable,
  • SMS/email notifications, and
  • airline approved.

Many exporters currently use USB temperature loggers which are generally discarded, or the data never accessed unless there is a dispute. So generally, there is no feedback of information to the exporter. A benefit of using remote temperature loggers is that the exporter can choose to receive alerts in ‘near real time’ so that decisions on the consignment can be made sooner rather than having to wait for it to arrive at the final destination, which could otherwise be too late.

Choosing a consignment monitoring technology - PDF opens in new window (Note: this document does not meet WCAG 2.0 accessibility guidelines.)

Air-freight study

In this study, Xsense® HiTag2 loggers (disposable wireless radio frequency temperature loggers) were used to remotely monitor air-freight consignments to two Asian markets.

Download this information as a pdf

Temperature Monitoring Technologies

Temperature technologies - a factsheet on temperature monitoring technologies (produced by Queensland Dept. Agriculture & Fisheries). PDF opens in new window (Note: this document does not meet WCAG 2.0 accessibility guidelines.)

Several companies such as Emerson, Escavox, Fresh Key, Frigga, Sensitech and Tive have developed new generation wireless SIM-based data loggers that are capable of monitoring different parameters such as temperature, light, relative humidity, shock and location in real-time. These innovative loggers have global coverage and work similarly to a mobile phone in that they connect to the nearest phone tower via 2/3/4/5G and autonomously upload data to cloud-based systems that can then be viewed on a handheld device or PC.

Real-time alerts via SMS or email can also be set up to notify users when product arrives at, or departs from pre-determined locations, and if consignment temperatures fluctuate outside set limits. These features come at a cost (e.g. a higher unit price and extra time to set them up compared to USB loggers) however, as export manager for Montague, Mark Bailey said “the main drawcard of these loggers is that the entire supply chain is more visible and in real-time so that potentially if there are any issues, then we can act on them in a more timely manner. For example, if we receive an alert and see the temperature increasing then we can contact the transport or shipping company and ask them to go and check it out”.

When deploying real-time loggers, it is recommended to start them 1 to 2 hours prior to positioning them in or on the top carton of the pallet closest to the door end of the shipping container so that there is minimal communication interference from the motor and water mass of the fresh produce. Temperature data and location may be updated en route depending on the location of the container on the vessel. If the shipping container is stacked in the middle of the vessel or when the vessel is out at sea, then the signal may be compromised. Information will be stored on the device until it comes into range with the next available mobile tower where data will be uploaded to internet cloud servers and accessible to approved users.

Scientist Glenn Hale, from Agriculture Victoria, discusses loggers used during temperature monitoring of stonefruit being exported overseas..
Video transcript

Part of the project is monitoring the cool chain in real time with these data loggers so that we can access the temperature in real time, and we can make decisions, by the time the fruit gets to the port or the dock. If there's been any problems, it's possible to to  change the strategy for marketing or even sales. There's many data loggers available in the marketplace. There's a few that we're trialling in this project, and it's looking at the accuracy and the consistency of the logos and also the functionality of them and how practical they are at gathering information for growers and exporters.  
This Emerson one is approved for airline use and also we've been using it for sea freight. This Sensitech logger we've been using for sea freight. SIM card based, they send a signal to a telecommunication tower. The data is then transferred to a data system, and it's accessible online or through the oversight website. One of the other logos we've been using is the Xsense. It works by radio frequency. So it sends a signal to a communication unit, and the data is downloaded when it's within 100 to 200 metres of this control unit. Another logger that we've been using is the Verigo logger. It works via Bluetooth. So the exporter or the importer can download an app to their mobile phone. They open up the app, it searches for active loggers in the area, and you click on a button and it will find the logger. It will download data and then you can send it via email or you can graph it as well.

Talk from Summerfruit Webinar series 2020: Managing fruit quality for export

Glenn Hale, from Agriculture Victoria, presents at the Summerfruit Industry webinar series 2020, talking on a key topic for industry:  Using real-time data loggers and dashboards
Webinar 26 August 2020 (26 min 15 sec)

Webinar presentation - PDF opens in new window (Note: this document does not meet WCAG 2.0 accessibility guidelines.)

Temperature and location data - real time example with table grapes

As part of the Serviced Supply Chains project, scientists at Agriculture Victoria recently deployed a real-time device (Frigga B9B) that successfully logged temperature and location data of a ‘Crimson Seedless’ table grape shipment and provided updates in Australia, Malaysia, Singapore and Indonesia (Figure 1). Transit time from packing in Robinvale (northern Victoria) to Surabaya (Indonesia) was approximately 28 days. Sea freight temperatures were maintained at approximately 1 °C with only minor fluctuations at the port in Singapore, but well within export limits. Another advantage of these loggers is that sensor reports can be downloaded at any time in either PDF, CSV or Excel format so users will always have access to the data.

Figure 1. A real-time temperature logger (inset) used to monitor a sea freight consignment of ‘Crimson Seedless’ table grapes from Australia to Indonesia. Map is a screen shot of the vessels route, which was taken from a dashboard developed by DAF, Queensland. Photo courtesy of Glenn Hale.


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