Agriculture Reference
In-Depth Information
from polyethylene plastic bags and Echegoyen and Ner
ยด
n(
2013
) from both poly-
propylene food containers and polyethylene plastic bags. The amount of silver
migration in those studies was found to be higher in acidic simulants, by increasing
temperature and time of contact and by microwave heating compared to a
regular oven.
There is also a study that has determined the mineral migration (Si, Mg, Fe) from
biodegradable starch/nanoclay nanocomposite films (Avella et al.
2005
) to pack-
aged vegetables. An insignificant increase in the levels of Mg or Fe was observed,
but a consistent increase was observed for Si, which is the main component of
nanoclay. Another work described the migration of nanosized layered double
hydroxide platelets from polylactide nanocomposite films (Schmidt et al.
2011
).
These studies, however, deal only with biodegradable materials and not with the
plastic nanocomposites containing nanoclay more likely to be used in food and
drink containers, such as PE, PET, and PP.
7.6 Labeling Applications
Many areas of packaging and labeling will probably be revolutionized by the use of
nanotechnology; previously impossible technical challenges to enhance products
will be overcome by using nanoscale coatings, which are usually three orders of
magnitude smaller than conventional inks particle size. Potential uses include
invisible brand protection coding, smart labels showing changes in temperature or
time, biohazard indicators for viruses or bacteria, or barrier treatments for papers.
Nano-barcodes are also hypothesized to be feasible.
Radio frequency identification devices (RFID) could be used for similar objec-
tives than the intelligent packaging with the advantage that the information on the
product can be electronically transferred from the product to different devices like
the refrigerator or a display in the shop. The consumers will be informed immedi-
ately of the status of a food product and when (or not) to consume it because RFID
chips can detect a target molecule. The requirement of a silicon chip as a substrate
for the high-frequency electronics could present a problem because it is not
expected to obtain low-cost RFIDs for use with foods until at least a decade.
Recently, some researchers (Jung et al.
2010
) have discovered a low-cost printable
transmitter that can be embedded in packaging in an invisible manner. It is based on
a carbon-nanotube-infused ink for ink-jet printers. The thin-film transistors are
made of ink; this is a key element in RFID tags that can now be printed on plastic
or paper. They expect to replace the bar codes with this roll-to-roll technique.
Other researchers (Quin et al.
2007
) have been studying how to use nanometer-
sized disks of gold and nickel to encrypt information. These nanodisks can form a
pattern much like a bar code, which means that each pattern would have a unique
response to a stimulus, such as electromagnetic radiation or light, depending on
what type of molecule (or molecules) is attached to the disks. Their small size
