10 May 2002

High-tech tools help to protect in-store spuds

Potatoes are delicate things. They appear to succumb

readily to all manner of pests and diseases and they dont

like being handled, stored or transported. Last weeks

Potato Storage Event, held at the home of British spuds,

Sutton Bridge Experimental Unit, highlighted the

problems, the cures and the preventative actions required

SPOTTING potential problems before they become real problems, would appear to be the overall message visitors received from the Potato Storage Event. It was an event well provisioned with companies and advisers keen to point out the worst catastrophes which can occur when storing potatoes.

Anyone doubting the seriousness of in-storage problems will wish to know that, according to event organiser the British Potato Council (BPC), potatoes to the value of £9m are lost through in-store bacterial and fungal infections each year.

The problem is knowing just when there is an element of rotting occurring in boxes or large heaps – discovering the disaster when potatoes are being prepared for market is usually too late.

The suggestion from one visitor that he paints a white line around the walls of his bulk potato store at fill level and sees if the potatoes sink, is clearly not now a workable approach to early problem detection.

A more useful solution may now soon be at hand through use of a novel system which uses an electronic nose to monitor boxes of potatoes and detect the early stages of soft rot.

A BPC-funded re-search project at Sutton Bridge with the University of the West of England, Bristol, samples air drawn through pipes placed within potato boxes. Taken at regular intervals, the analysing unit detects the volatile organic compounds generated by potatoes infected by bacterial soft rot (Erwinia carotovora) and provides an early warning – by as much as eight weeks, it is claimed.

According to the universitys Peter Spencer-Phillips, this warning would enable the store manager to deal with the problem – by increasing the ventilation or sending the crop to market at an earlier than planned date, for example.

Trials with the system earlier this year are reported to have been promising with it being claimed that it is now possible to detect one tuber with mild soft rot in a 25kg sack of potatoes.

Further trials later this year could see the system available commercially within two years. And with an element of miniaturisation, Dr Spencer-Phillips believes a hand held version which would be simply held over the potatoes could also be a reality in the future.

Key to healthy stored potatoes is to create and maintain the correct environment. It is a message not lost on the industry which is now able to provide a number of environment control systems.

According to Robydomes Peter Watts, no large-scale potato grower can now afford to be without a good storage system.

"The value of potatoes means that their in-storage management has to be first class," he says. "There is simply too much money at risk to think otherwise."

Latest entrant from Robydome is a computerised system with touch screen activation for the environment control of up to eight stores. And the system can be operated remotely – from the farm office, for example.

Sensors in the stores provide information regarding temperature, humidity and ventilation status. Changes in the stores, should they be required, are implemented by touching the appropriate command on the screen menu.

PC compatible to allow software updates to be easily made, a print out of the storage history of potatoes also enables purchasers – supermarkets, for example – to have full knowledge of the crop – crop traceability.

Price of the Robydome control system starts at about £5000 for, say, one store. The addition of further stores to the same system reduces the net cost/store so that a three-store system may cost about £7500. &#42

Above: An electronic nose has been developed by the University of the West of England, Bristol which can provide up to eight weeks warning of the presence of bacterial soft rot in potatoes.