Biomedical Engineering Reference
In-Depth Information
the package (Brody 2006). Which of these strategies is used strongly depends
on the product to be protected, the packaging concept, and price.
5.4.2 Antimicrobial Activity
For some products, deprivation of oxygen is not an option and microbial
activity is difficult to stop. However, here, nanotechnologies can help by
enabling antimicrobial activity in or on the packaging material (Cha and
Chinnan 2004). It is well known that nanosilver particles, already widely
used in wound dressings and textiles, work as antimicrobial agents. By
incorporating nanosilver particles into the matrix of the packaging material,
microbes that come in contact with these materials are killed. This effect
reduces the microbial pressure on the food product inside, effectively pro-
longing its shelf life. Unfortunately, nanosilver is a persistent nanoparticle
that can exert its action even after its intended use, making it a potential
environmental hazard. Nanothick layers of polymer brushes that have posi-
tively charged atoms incorporated in them have the same effect, but are
much better attached to the packaging material and will be destroyed when
incinerated or will degrade when discarded, although this might take some
time.
5.4.3 Monitoring Quality Deterioration
Even after effective packaging or other measures, there are only very few
food products that can be stored for a very long time. This means that pro-
cesses that are responsible for quality deterioration are only slowed but not
stopped. (Some of these processes are actually desirable and by maturing the
product, its quality can be improved. However, these processes are beyond
the scope of this chapter.) Having information on the quality and safety of
the product is very important to the consumer. Until now, the quality of a
product is assessed based on the storage time, sell-by date, or consume-by
date. This is an indirect method that relies on the manufacturer models of
the spoilage process and on the reliability of storage conditions. Especially
when the product has to be stored at a low temperature or other conditions
that are not maintained easily, there is a chance that this requirement is not
fulfilled the entire time the product in storage. In these cases, the quality
may not be in agreement with the sell-by or consume-by date, and consump-
tion of the product could cause health problems. A better system is based on
the product of time and storage temperature, which is used by Onvu ( www.
onvu.com ) . The food industry has done a tremendous job in controlling large
parts of the chain that is necessary to bring the product from primary pro-
duction to the consumer's plate, resulting in a very high level of food safety
in industrialized countries. Unfortunately, there are still parts of the chain
that cannot be controlled. Especially, storage by the consumer is highly unre-
liable and can cause serious problems.
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