Biomedical Engineering Reference
In-Depth Information
To overcome this problem, it would be better to have a direct indication of
the quality of the product inside a package. Spoilage processes often have
characteristic volatiles as by-products. As a matter of fact, we become aware
of these volatiles when we perceive that a product smells “off.” Unfortunately,
our nose is not very sensitive and we can only use this method on an open
package and if the concentration of the volatiles is diluted in the ambient
atmosphere. This means that we can only rely on this method of quality
assessment in very specific cases. With nanotechnology, it is possible to cre-
ate devices that are much more sensitive to the specific volatile molecules
associated with the spoilage process of the product packaged. Moreover, by
including them in the packaging concept, they can monitor the atmosphere
inside the packaging where the concentration of these molecules will be
highest.
The detection of the presence of (too high concentrations of) the volatiles
can be done through a chemical reaction resulting in a color change or other
visible signals. This can be effective for the individual consumer but is diffi-
cult to incorporate in a more complex logistical system that optimizes storage
times, delivery distance, and optimal consumer quality. Such a computer-
ized system needs sensors that can be read electronically. These sensors can
be combined with RFID systems to communicate wirelessly with the logistic
system outside. With such a concept, it would also be possible to assess the
quality of the product at the checkout counter and maybe automatically give
a price reduction on the basis of the remaining storage time. In the further
future, such devices would also be able to communicate with home appli-
ances, such as refrigerators, to signal that consumption is required before the
product is spoiled.
Quality sensing devices based on nanotechnologies and incorporated in
the packaging concept will, in most cases, need to be disposable. Not only
does this limit the possibilities from an environmental point of view, it also
necessitates a production method that makes them very cheap. With nano-
technologies, which usually have economic advantages when produced in
large quantities, and especially when advances in other fields of nanotechnol-
ogy research make it possible to print these types of electronic circuitry on
packaging materials, these concepts will become viable (
www.polyapply.org
).
5.4.4 Detection of Spoilage Organisms
Raw materials for food and primary food products are always infected with
certain bacteria and other organisms. These organisms after harvest start to
propagate and eventually spoil the product. The amount of spoilage organ-
isms in combination with storage conditions and models for the spoilage
processes can be used to accurately predict quality deterioration of the prod-
uct and therefore allows logistical decisions about where to market the spe-
cific, usually fresh product. Unfortunately, it requires extensive laboratories,
qualified personnel, and especially time for the determination of the amount
