Detecting food spoilage with optical sensor

By Joseph James Whitworth

- Last updated on GMT

The sensor to be used in the CheckPack project
The sensor to be used in the CheckPack project

Related tags Food safety Sensor

An optical sensor that can detect spoilage in food products is being developed to cut down waste and extend shelf life.

The hope is the sensor, which is integrated in the packaging material will be able to sense the quality status of the food via adsorption of volatile biomarkers on selective materials which are coated on the sensor surface.

Researchers will identify and quantity the most important volatile compounds released during spoilage processes, for different packaging conditions.

Meat and fish focus

Dr Mike Vanderroost, CheckPack coordinator, told that it is initially focussed on meat and fish packaged under modified atmosphere packaging (MAP).

“Initially we will look at MA packaged meat and fish but in the future when this project is finished, we will expand into fruit and vegetables, baked products and other industries such as cosmetics,” ​he said.

“The big goal is to make it practical for industry but the upscale would likely be after five years.”

CheckPack, launched in November last year, will run for four years and has €2.6m of funding from IWT, a Flemish government agency for Innovation by Science and Technology.

It is a collaboration between Ghent University, KU Leuven, Vrije Universiteit Brussel and Radboud Universiteit Nijmegen. 

Food2Know will be responsible for valorization and dissemination of the project results.

How it works

When the volatile compounds interact with the coating materials, a change of the refractive index of these materials will occur, said Vanderroost.

This change can be sensed by infrared light that is directed towards the sensor (like a barcode scanner).

The refractive index change will cause a wavelength shift of the infrared light which is reflected by the sensor. 

Based on the wavelength shift of the reflected light it is then possible to extract information about the volatile compounds and their concentrations inside the package, using a mathematical model that will be developed during the project.  

Challenges to overcome

He said the different components and principles of the sensor exist, the challenge is to put it together and make it work in this context.

“A challenge is to determine the volatile compounds released during spoilage and the microorganisms responsible for the production of these volatile compounds and link the concentration to spoilage in the food.

“We need to select the coating materials that can adsorb volatile compounds and they still have to be developed during the project.

“They will be coated on optical sensors with a surface of a few square millimetres.

“A mathematical model will be able to link the output signal of the sensor to the quality status of food products to see if there is spoilage or no spoilage.”

Prototype development

Vanderroost, who works in the department of food safety and food quality at Ghent University, said the aim is to develop a prototype, one sensor to prove it works before progressing further.

“New technology is important because the Foods and Agricultural Organisation (FAO) of the United Nations (UN) say about one third of food produced for human consumption is lost or wasted every year.

“The sensor could replace expiry dates on food packages, consumers think that the food is not consumable and they throw it away, the sensor makes it possible to expand storage in the fridge.”

Reduce food waste

He said the technology can help to reduce number of food lost and wasted.

“There are sensors, which is the area we are in, indicators which change colour based on something that happens inside the pack and RFID tags which are already used.

“We have a lab at Ghent University with expertise to determine and quantify microorganisms and volatile compounds.

“There is a research group with expertise in mathematical modelling that is able to link sensor signals to volatile compound concentrations to be able to tell whether a product is spoiled based on the response of the sensor.

"A big advantage is the production process currently used for semi-conductors that are produced is more or less the same, so upscaling the production is not a problem and this means we can keep the price low.”

Related topics Food Safety & Quality

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