LIGHT! 003 | Photonics revolutionise the food industry

WINE AND OLIVE OIL
IMN · CSIC
Quality detection of food
via your mobile
The Institute of Micro and Nanotechnology (IMN) of
the National Scientific Research Council in Spain (CSIC)
has developed an optical sensor with several advantages
including remote optical detection and no need
for marking, that is easy to use and does not require
complicated optical systems or large magnification for
detection purposes, since it can be used by means of
a smartphone. The sensor’s manufacturing process is
simple and very low cost, offering potential for largescale
production. The sensor can find a practical use
in applications that require rapid, simple and portable
detection, as is the case in the detection of quality in
certain foods. In particular, the sensor is especially indicated
for the detection of liquid or viscous substance
mixtures, such as bio-solutions or liquid or viscous
food products such as water, oils, alcohol, wines, etc.
This sensor is manufactured on thin glass or plastic of
approximately 1x1 cm in size. It incorporates a dense
network of metallic nano-threads manufactured using
a simple nano-stamping technique developed at the
IMN-CSIC. The nano-threads are especially sensitive
to the environment that surrounds them and, when
they are in contact with the medium to be detected
(for example, when depositing a drop of the sample on
them), they produce a change in the optical signal detected
through the video camera on a mobile phone.
This change is evaluated using an application specifically
designed for detection.
The sensor measures the optical properties of the
medium in which it is submerged, so its use is very
wide-ranging. Some examples of applications include
the determination of alcohol in water, by measuring
concentrations of up to 3% in the volume of a drop
of water; determination of the purity of an olive oil
(whether or not it is mixed with other substances, other
oils or even if it is of an extra or another category);
determination of the quality and concentration of alcohol,
for example in both beverages with a high alco-
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