New technology is helping give consumers peace of mind by making food contamination checks easier.

As human activities go, few are more basic than eating, and people are more conscious of what they eat than ever. Many fret about foodstuffs and processed foods that earlier generations would have eaten without a second thought.

Food-producing regions and processors can be devastated by a single instance of contamination. But new technologies may help put consumers’ minds at ease and improve the safety of what goes into our mouths.

One of the things people worry most about is agrochemicals. According to a 2015 survey of 12,000 people by MyVoice Communications, an online research company in Tokyo, 60% said they felt at least somewhat uneasy about food safety, and 57% of those said they worry about chemical residues in food.

Break it down

At present, one of the best ways to detect chemicals in food is chromatography. This is a method of separating out substances dissolved in liquids or gases and measuring their components based on how quickly they separate out and in what quantities. Liquid chromatography is used to analyze substances dissolved in liquids. In gas chromatography, the substance being analyzed is heated to around 300 C until it vaporizes. Substances that break down at higher temperatures cannot be analyzed using this technique.

Both approaches have their drawbacks: Liquid chromatography, as its name implies, works only with liquids; the high temperatures used in gas chromatography can destroy the substances one is trying to examine.

Shimadzu, a Kyoto-based precision instruments maker, has come up with a new way of peering into stuff, which it calls Nexera UC — for “unified chromatography.” This method uses carbon dioxide that has been transformed by heat and high pressure into a supercritical fluid, giving it the properties of both a liquid and a gas.

This supercritical fluid is used as a solvent to break the substance being analyzed into its component parts. And because carbon dioxide goes supercritical at around 31.1 C and 7.4 megapascals of pressure, there is little danger of the components being destroyed, as happens at higher temperatures.

Another advantage of the system is that it allows substances that previously required separate gas and fluid chromatography procedures to be examined in a single step. As many as 500 agrochemical components can be analyzed at once.

Nexera UC also simplifies preparation. With conventional tests, it is necessary to pulverize farm produce, then mix in a solvent and finally add a reagent to check for chemical reactions. Test results can vary, depending on the skill of the tester. Shimadzu’s system takes advantage of the supercritical carbon dioxide’s properties as a solvent and incorporates new drying technologies to make crushing easier. The company says this shortens preparation time from 35 minutes to five minutes.

Miyazaki Prefecture has set up a facility to analyze agrochemical residues using Nexera UC. The aim is to highlight the safety of produce from the prefecture to appeal to consumers. The system is expected to become popular elsewhere because it makes detecting agrochemicals easier.

In November, Japan eased regulations on those who use small quantities of gas — such as carbon dioxide — in their work. Such companies and municipalities no longer have to file paperwork. This will make it easier for them to use the Nexera UC system.

Looking in

Given consumer worries about contamination, food processors are generally very careful about quality control at their plants. Still, there are endless reports of foreign substances winding up in food. One promising method of discovering them before they make it to the kitchen is using terahertz waves.

These electromagnetic waves have wavelengths that lie between those of visible light and radio waves, giving them the properties of both. They pass through soft substances such as resin that are impenetrable to light, but are reflected by metals. They can thus be used to scan paper or plastic packaging to detect foreign objects.

X-rays are typically used to examine the contents of boxes and bags. Because terahertz waves do not penetrate as readily as x-rays, they cannot scan as deeply. On the other hand, they are safer than x-rays and easier to use because they do not require the operator to wear protective clothing. They also consume less electricity.

Several years ago, Rohm, a Kyoto manufacturer of electronic parts, developed tiny components that emit terahertz waves. Consumer electronics company Pioneer makes scanners that use these components. The main advantage of these devices is their compactness and portability.

Pioneer is also developing precision equipment for use in the restoration of the Takamatsuzuka Tomb — an ancient burial chamber in Japan’s western Nara Prefecture. The equipment is also expected to have applications in food testing.

To be practical, the scanners will need to work faster. Pioneer hopes to develop a system in the next fiscal year that can quickly create stable images using terahertz waves. Nagoya Institute of Technology and NTT Electronics last year developed food testing equipment that uses terahertz waves; they hope to begin field trials before the end of this fiscal year.

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