Singapore engineers invent artificial nose to test freshness of meat

A team of engineers at Nanyang Technological University (NTU) in Singapore have invented an artificial nose designed to be able to react to the gases in meat to detect whether or not it is fresh.

The electric nose, or e-nose, has been designed to react in a similar way to the system found in mammals by detecting odours and flavours.

The team hope the invention can help reduce food waste by helping users assess whether or not meat is safe to consume with a 98.5% accuracy.

The nose contains a barcode made of chitosan, a type of sugar, which is fitted with dyes that act as receptors for the gases produced when the meat starts to decay.

In the mammal's system, the brain collects and analyses the scents picked up by the nose and organises them into patterns, allowing the mammal to recognise the odour present as the meat ages and begins to rot.

Professor Chen Xiaodong, director of the Innovative Centre for Flexible Devices at NTU said: “These barcodes help consumers to save money by ensuring they do not discard products that are still fit for consumption, which also helps the environment. The biodegradable and non-toxic nature of the barcodes also means they could be safely applied in all parts of the food supply chain to ensure food freshness."

The dyes on the barcode will change colour depending on the different concentrations of gases present, providing a unique variety of indicators for what the team call the "scent fingerprint."

The idea of an artificial nose was first proposed by Alexander Graham Bell in 1914.

According to a paper released by the team at NTU, the efficacy of the product has remained accurate after having been tested on chicken, fish and beef meat samples that were left to age.

The team have filed a patent for the product and are now awaiting confirmation from a Singapore agrifood business to extend the product to other kinds of perishables.

When testing the product, the team developed a classification system (fresh, less fresh, spoiled) to give them an idea of the state of the products they were testing using an international standard that determines meat freshness.

This is done by extracting and measuring the amount of ammonia and bioamines present in fish packages wrapped in a transparent polyvinyl chloride and stored at 4°C over five days at different intervals.

This allows them to use the barcode at the side without touching the product, which could contaminate the readings.

The team claim the nose is 100% accurate at detecting meat products that are spoiled as well as less fresh meat being detected with a 96-98% efficacy, according to the research paper.

Professor Chen said: "We are working towards providing a broadly applicable new platform for food quality control. While e-noses have been extensively researched, there are still bottlenecks to their commercialisation due to current prototypes’ issues with accurately detecting and identifying the odour.

"We need a system that has both a robust sensor set-up and a data analysis method that can accurately predict scent fingerprints, which is what our e-nose offers.”

"Our proof-of-concept artificial olfactory system, which we tested in real-life scenarios, can be easily integrated into packaging materials and yields results in a short time without the bulky wiring used for electrical signal collection in some e-noses that were developed recently."

He added:

These barcodes help consumers to save money by ensuring that they do not discard products that are still fit for consumption, which also helps the environment.

"The biodegradable and non-toxic nature of the barcodes also means they could be safely applied in all parts of the food supply chain to ensure food freshness."

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