14 May 2012 Should iEat? Testing food with a smartphone
“Everyone’s a critic,” sighs the artist. But with new smartphone technology, we could take our criticism to new mediums and industries entirely. “Everyone’s a quality tester,” the industrial food producer may soon be sighing.
Germany’s Fraunhofer Institute is developing a miniature spectrometer that Food Production Daily says “will pave the way for instant quality analysis of whether fruit is ripe or if meat contains too much water”.
The device, which is smaller than a sugar cube, uses near infrared technology to assess starch, protein, water, and fat content in food – and you wouldn’t even have to unwrap the goods to test them, since the spectrometer works across a thin layer of plastic. The device won’t be able to perform microbiological or toxicological analysis, according to Fraunhofer – but it will be able to see if food is ripe or water-logged, and give you instant advice on whether to buy or not.
You know the type (and maybe you are one, yourself): the man who spends a solid three minutes squeezing each and every plum in search of the perfectly ripe one, or the woman who holds the ground beef up to the light, scrutinising it from multiple angles. Now imagine hordes of these people whipping out their smartphones and scanning item after item, package after package. This may be our food-shopping future.
The technology itself is not entirely novel, according to Fraunhofer. The principles here are well understood: simply shine broad-bandwidth light on a piece of food, which will reflect different near infrared wavelengths of varying intensities. A device measuring the spectrum reflected back can then infer the properties of the item being scanned.
The real breakthroughs here are the ways Fraunhofer has shrunk the technology and inched it towards affordability (and therefore, commercialisation).
They’ve hacked a clever way of automating the mass production of the things, by using large silicon wafers capable of holding the components of hundreds of the spectrometers. (It’s a two-step process actually, wherein wafers with integrated components and wafers with optical components are stacked and fused–and it yields stronger spectrometers than traditional manufacturing by hand, reportedly.)
In a follow-up piece, Food Production Daily wondered whether the tech would render professional food technologists obsolete?
Far from it, replied Stephen White of Qadex, a food safety company. He said that the device might in fact create “more work and headaches, with the need to respond swiftly as issues emerge on social media which are outside the control of the food industry.”
Food, incidentally, isn’t the only industry that stands to be transformed by the democratization of quality testing; cosmetics is another one, reports CosmeticsDesign-Europe.com. And Fraunhofer, in its initial release, suggested that the device could also detect forgeries, test drugs, and even show whether a car has been repainted or not.
Source: Technology Review, published by MIT
Comparing apples and oranges
Every year, supermarkets lose a significant quantity of their fruits and vegetables to spoilage. To help combat those losses, MIT chemistry professor Timothy Swager and his students have devised a new sensor that could help grocers and food distributors better monitor their produce at an affordable cost.
The new sensors, described in the journal Angewandte Chemie, can detect tiny amounts of ethylene, a gas that promotes ripening in plants. Swager envisions the inexpensive sensors attached to cardboard boxes of produce and scanned with a handheld device that would reveal the contents’ ripeness. That way, grocers would know when to put certain items on sale to move them before they get too ripe.
“If we can create equipment that will help grocery stores manage things more precisely, and maybe lower their losses by 30 percent, that would be huge,” says Swager, the John D MacArthur Professor of Chemistry.
Detecting gases to monitor the food supply is a new area of interest for Swager, whose previous research has focused on sensors to detect explosives or chemical and biological warfare agents.
“Food is something that is really important to create sensors around, and we’re going after food in a broad sense,” Swager says. He is also pursuing monitors that could detect when food becomes mouldy or develops bacterial growth, but as his first target, he chose ethylene, a plant hormone that controls ripening.
Plants secrete varying amounts of ethylene throughout their maturation process. For example, bananas will stay green until they release enough ethylene to start the ripening process. Once ripening begins, more ethylene is produced, and the ripening accelerates. If that perfect yellow banana is not eaten at peak ripeness, ethylene will turn it brown and mushy.
Fruit distributors try to slow this process by keeping ethylene levels very low in their warehouses. Such warehouses employ monitors that use gas chromatography or mass spectroscopy, which can separate gases and analyze their composition. Those systems cost around $1,200 each.
“Right now, the only time people monitor ethylene is in these huge facilities, because the equipment’s very expensive,” Swager says.
Detecting ripeness
Funded by the US Army Office of Research through MIT’s Institute for Soldier Nanotechnologies, the MIT team built a sensor consisting of an array of tens of thousands of carbon nanotubes: sheets of carbon atoms rolled into cylinders that act as “superhighways” for electron flow.
To modify the tubes to detect ethylene gas, the researchers added copper atoms, which serve as “speed bumps” to slow the flowing electrons. “Anytime you put something on these nanotubes, you’re making speed bumps, because you’re taking this perfect, pristine system and you’re putting something on it,” Swager says.
Copper atoms slow the electrons a little bit, but when ethylene is present, it binds to the copper atoms and slows the electrons even more. By measuring how much the electrons slow down — a property also known as resistance — the researchers can determine how much ethylene is present.
To make the device even more sensitive, the researchers added tiny beads of polystyrene, which absorbs ethylene and concentrates it near the carbon nanotubes. With their latest version, the researchers can detect concentrations of ethylene as low as 0.5 parts per million. The concentration required for fruit ripening is usually between 0.1 and one part per million.
The researchers tested their sensors on several types of fruit — banana, avocado, apple, pear and orange — and were able to accurately measure their ripeness by detecting how much ethylene the fruits secreted.
John Saffell, the technical director at Alphasense, a company that develops sensors, describes the MIT team’s approach as rigorous and focused. “This sensor, if designed and implemented correctly, could significantly reduce the level of fruit spoilage during shipping,” he says.
“At any given time, there are thousands of cargo containers on the seas, transporting fruit and hoping that they arrive at their destination with the correct degree of ripeness,” adds Saffell, who was not involved in this research. “Expensive analytical systems can monitor ethylene generation, but in the cost-sensitive shipping business, they are not economically viable for most of shipped fruit.”…..