Electronic Nose ‘Smells’ Soft Rots in Stores
This article first appeared in AusVeg’s publication, Potatoes Australia here.
Early identification of soft rots in potato stores may soon become easier thanks to a newly-developed electronic nose. The University of Warwick in the United Kingdom has developed a new tool which replicates the function of the human nose and is capable of detecting odours released by these rots. Heather Briggs from AusVeg spoke to project lead Dr James Covington and storage specialist Dr Glyn Harper from Sutton Bridge Crop Storage Research about this novel technology.
Rots are one of the biggest in-store challenges for potatoes and if they remain undetected, they can quickly pass on from one potato to another. This means timely decisions need to be made before the disease becomes established as consignments may be rejected, resulting in significant financial losses.
The first signs of rot are normally perceived by the store manager’s nose, once a rot has started. However, a system which is sufficiently sensitive to detect these odours well below the human level – and perhaps even before symptoms occur – may provide more opportunities for action to be taken in the store to prevent its spread.
MODELLING THE HUMAN NOSE
University of Warwick School of Engineering Associate Professor Dr James Covington explained that the electronic nose instrument works by sampling the store air and then using an array of gas sensors that respond to different odours produced, which together can detect bacterial infection from other odours in store.
“These instruments could be deployed anywhere in store to identify the location of the problem,” Dr Covington said.
His idea is to optimise off-the-shelf commercial gas sensors to reduce the development time of the electric nose instrument for detecting rots. Commercial sensors in his electronic nose instrument have been trialled in store environments.
Dr Covington and his team looked at detection throughout different stages of soft rot development in a laboratory environment, collecting and analysing data to help choose the best type of gas sensors from the many which are already commercially available.
Results from the work were successful, and they found an instrument which is capable of detecting differences between diseased and infected tubers.
“What is really important is that it can detect these chemical signature changes before physical or olfactory signs of rot appear,” Dr Covington said.
However, he cautions, this initial work was conducted under laboratory conditions rather than in a large potato store.
Dr Covington and his team then worked on developing a new prototype instrument which could make early detection of rots, testing it at the Sutton Bridge Crop Storage Research (SBCSR) facility. The SBCSR is owned by the Agriculture & Horticulture Development Board (AHDB) and is operated by the Research Division under the 'AHDB Potatoes' banner.
Potato storage specialist and plant pathologist Dr Glyn Harper, who was in charge of testing at SBCSR, noted that in a commercial store the electronic noses can be placed within the circulating ventilation system, in boxes or between the stacks or even within the bulk pile.
“This means that the detectors can work in both box and bulk stores. Moreover, they may be able to collect other important information on the storage environment, such as temperature, humidity, carbon dioxide levels, as well as other parameters such as light, noise and particles,” Dr Harper said.
Trials then moved on to looking at larger scale stores to find out how well they fitted into commercial store management systems with very positive results, according to Dr Covington.
“The sensors not only detected the presence of a rot but also the location within the store, providing store managers with useful information on which area to deal with as a priority,” he said.
Dr Harper added that increasing ventilation, changing the environment or even deciding to take the crop out of store sooner than originally planned and sell it before the rots set in, may also be useful strategies to take.
Dr Covington said that the sensors have the potential to detect odours from other tuber diseases and conditions.
“There is the possibility that alternative gas sensors could be used to fulfil other store needs, such as bacterial load at harvest, or to monitor sprouting, so a timely top-up application of sprout control can be made before sprouting occurs,” Dr Covington said.
“Processing systems depend on technology and sensors that are already being used in stores to monitor temperature, carbon dioxide and humidity to fine-tune environmental control. This could be an additional system that will help the potato industry keep on top of its game.”
He goes on to point out that the instrument has useful potential for transport of seed potatoes as the electronic nose could also play a role when infection occurs during storage and transit.
“The main concern of importers is that rots appear post-inspection after arrival at their destination. These can degrade rapidly and, in some cases, result in total loss. Therefore, following the current pre-shipment testing with molecular and microbial detectors to monitor the crop throughout the time spent in transit, it would facilitate the right management decisions.”
For more information, please visit www.warwick.ac.uk
This communication has been funded by Hort Innovation using the fresh potato research and development levy and contributions from the Australian Government.