Wising up to food safety – smartphone sensors for the sensible shopper

Smartphone applications are already widely-used by consumers to scan the barcodes on food products, revealing everything from nutritional information to calorie counts and even advising those who suffer from allergies whether a particular product is suitable for them.

But the shoppers of the future may be able to use their mobile phones to get an even deeper insight into the food they take home, thanks to a new, miniature spectroscopic device that can instantly analyse whether fruit is ripe, or meat too fatty.

The tiny device, smaller than a sugar cube, which could – in the future – be installed in smartphones, uses near infrared technology to assess starch, protein, water and fat content in food. And consumers wouldn’t even need to break the packaging to test the products, as the system can take measurements straight through a thin layer of plastic film.

So how does the technology work? The device, developed by researchers at the Germany-based Fraunhofer Institute, shines a broad bandwidth of light on the item to be tested – for example, a piece of meat. Then, depending on the meat’s composition, it reflects different wavelengths of light in the near infrared range with different intensities. The resulting spectrum tells the user what amounts of which substances are present in the product. And, when the technology is developed into a smartphone application, it will be able to advise consumers whether or not to buy a particular piece of food.

"Customers are becoming more sensitive about what they buy and this technology could allow the customer to buy the product that fits best to their personal taste," said Dr Heinrich Grüger, who manages the relevant business unit at the Fraunhofer Institute for Photonic Microsystems (IPMS) in Dresden. "In the future I believe they will be interested in having solid data about food products, rather than just reading the label someone else has attached onto the packaging."

Is handheld food sensor technology affordable?

Of course, the spectrometer is not a new invention and there are many forms of this device available commercially. What’s different about Grüger’s version, though, is its size. With a volume of only 2.1cc, it is 30% smaller than a sugar cube and around 350 times more compact than its commercial counterparts, making it suitable for installation into a smartphone. Moreover, it can be mass produced, significantly increasing its affordability.

While spectrometers are usually manufactured by assembling and aligning each component – mirrors, optical gaps, grating and detector – individually, the mini spectrometer developed at Fraunhofer can be produced using large silicon wafers capable of holding the components of hundreds of these devices. Essentially, wafers with integrated components and wafers with optical components are stacked on top of each other and fused; they are then isolated to form individual spectrometers.

However, this has not yet been implemented on a large scale, and the cost of mass production is still too high to produce these devices commercially. "Potentially, we have realised the technology that can enable volume production to produce these devices at a very reasonable price in terms of spectroscopic equipment," Grüger said.

But this is a long way from the price a mobile phone company would be willing to pay to use a spectrometer in a smartphone. "The most expensive component of an iPhone up until now is the display, for which companies pay about $5, but producing a spectrometer for under $10 with a resolution appropriate for this application is a very tricky thing," Grüger admitted.

However, work is underway to both reduce production costs to a level those in the mobile phone business would accept, and optimise the technology. "Currently engineers and scientists carry out final assembly, but we are working on an automated process to do this. If we want to produce several thousands or even millions of these devices, the process has to be fully automated," Grüger explained.

"We are also working on optimising the system, particularly the signal to noise ratio, which is very important for spectroscopic applications."

Consumer uptake only five years away

So how long will it be before consumers are actually able to use these devices via their smartphones to measure food quality? At least five years, according to Grüger.

"We now have the spectrometer as a standalone device but it will be a several step path to the final product," he explained. "I think the next step will be the implementation of spectroscopic equipment at the point of sale, for example in the weighing scales at the grocery or at the butchers. Consumers would then not only be able to buy a specific mass of product, they would also get information about the product’s composition. I believe this will happen in three to five years.

"With increasing sales and decreasing price of spectrometers following this, we would then look to implement higher volume production, moving closer, step by step, to the market of mobile devices. But this also depends on the customer – whether he is happy with having a spectrometer at the point of sale, or would prefer to have it in a mobile device."

There is also a lot more than merely the hardware to take into account. "You also need the software that is implemented in the device," Grüger emphasised. "The user will definitely not be a spectroscopic engineer or expert so it has to be realised in a way the layman is able to use."

Moreover, a database needs to be created where users can download the reference data necessary to analyse the quality of food products. "We have already started working on this at Fraunhofer," Grüger remarked.

Positive feedback

Although food quality detection is not likely to overtake barcode scanning in the App Store chart any time soon, the feedback Grüger has had from potential customers suggests it could definitely be a technology for the future.

"We have presented this device at different fairs and been in contact with potential users and producers and they have certainly signalled interest in this technology," he stressed.

Many in the food industry, too, only see the advancement of detection technology as a positive step. "Developments in methods of detection and lab-on-a-chip technologies have resulted in useful applications in food production and processing. The reduced cost and size of detectors, for example, have made it easier to detect pathogens along the food supply chain, from farm to processing plants and distribution centres and can inform the development of more targeted and effective food safety and food quality systems," said Barbara Gallani, director of food, safety, science and health at the UK’s Food and Drink Federation.

"While consumer uptake of infrared spectrometers might not be exactly around the corner, the use of intelligent and active packaging to monitor freshness and display information on quality certainly is."

As mass production costs come down, mini-spectrometer technology is further honed by researchers, and a solid infrastructure for potential smartphone applications is developed, consumer food quality testing is merely the next step. "Increasingly, customers don’t want to rely on what is printed on the box," Grüger concluded.

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