Food gas sensor could show
when fruit is ripe and meat fresh
Source of Article: http://www.foodproductiondaily.com/Supply-Chain/Food-gas-sensor-could-show-when-fruit-is-ripe-and-meat-fresh
By Rory Harrington, 05-Aug-2009
A new sensor that analyses gases given
off by foods could be used to check their safety, quality and reliability
quickly and economically, said the German research team behind the device.
Food suppliers could accurately gauge the ripeness of fruit stored
in a warehouse to know when best to deliver it to a supermarket or whether
fish or meat is still fresh, team member Dr Mark Buecking told FoodProductionDaily.com.
Volatile components
Developed by researchers at the Fraunhofer Institutes for Molecular
Biology and Applied Ecology IME and the Physical Measurement Techniques IPM
in Freiburg, the novel system uses volatile components to check for characteristics
such as ripeness or freshness.
Using either a hand-held or fixed device, a sensor with a surface
heated to high temperatures analyses the gas emitted by food before
displaying colour-coded results on a screen; green for optimum level of
ripeness or freshness; yellow to indicate it is not quite ready, and red to
show either the produce needs more time to mature or has spoiled in the
case of meat or fish.
Metal oxide sensors
"We have brought together various technologies based on the use
of metal oxide sensors, similar to those installed in cars, for example, to
close ventilation vents when driving through a tunnel,” said Buecking.
“Researchers at IPM have developed these sensors further. If a gas
flows over the sensor, at temperatures of 300 to 400°C, it will burn at the
point of contact. The subsequent exchange of electrons changes the
electrical conductivity.”
It is this change that allows the instrument to evaluate the gases
and come up with a reading.
Black box
Buecking explained that before the gas reaches these sensors, it has
to go through a separation column with polymers that filters out substances
and allows them to analysed individually or disregarded if they play no
part in the process. The analytical software, contained in a so-called
black box, can be changed or recalibrated according to the food being
checked.
The group has already developed a prototype and the system is
currently being tested in the German pork sector. The project aims to
develop an on-line device used on the slaughter line that is able to detect
an unpleasant off-flavour in male pigs, known as boar taint – which can
arise as a result of the production of sexual hormones.
Buecking explained: “It's true that most pigs are slaughtered
well before sexual maturity – before any odorous substances have formed. As
there is the risk, however, that some boars could produce odorous
substances prematurely, all boars are castrated when they are young
piglets. Castration may not be necessary in the future if the pork could be
tested on-line before it is packaged.”
He said the group was in general interested in teaming up with
appropriate companies to discuss manufacturing the system on a commercial
basis and hoped to bring the system to market within two years.
Supply chain benefits
The benefits of the system to those involved in the supply chain
could be numerous and important, said Buecking.
“The robust and easy-to-handle system is fast and facilitates
detection in minutes instead of hours or days,”
he said. “It can be implemented into the process itself as well as into
a quality management system via a network to record and
store data on a digital basis. We also believe it is economical compared to
laboratory tests, which are slower and costlier.”
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