food

packaging
27
Coated film gets rid of moulds
and microbes
Film-packaged foodstuffs often contain added preservatives such
as benzoic or sorbic acid, but it is clearly better to have as few
additives as possible in food.
This is why scientists at the
Fraunhofer Institute for Process
Engineering and Packaging IVV,
have opted for a different way of
getting rid of moulds and
microbes. Instead of adding
preservatives to the food, they
coat the packaging film with them.
How it works
Any type of flexible foil can be
varnished without affecting its
basic properties (moisture or
oxygen barrier). A layer containing
anti-microbial activity can then be
applied as an additional feature.
From a technical point of view
coating is a simple, well
established process, and no
special devices have to be
developed. The only special
component is the composition of
the coating, consisting of a carrier
material and anti-microbial
additives. The carriers have to
provide proper adhesion and
sufficient release of the active
agents; and can be either
ORMOCERS,
inorganic/organichybride ploymers
developed by the Fraunhofer
Institute for Silicate Chemistry in
Würzburg, or a special
composition of organic polymers
under development. The coating
process is simple, and in the
Institute’s pilot plant a reel
process
is used. The film passes a coating
station followed by a drying
device (UV-curing in the case of
ORMOCERS).
The main challenges were to
discover active substances with
suitable release behaviour that
were food-compatible (benzoic or
sorbic acid) and to scale up the
transfer of the coating process
from laboratory scale to industrial
scale. The Institute is still working
on the latter challenge.
Applications
The film costs only marginally
more than normal film, as the
components are inexpensive, and
it can be used for all types of solid
food where the film directly covers
the food surface. Since it is only
the contact surface that is
protected by the small amounts of
released active agents, it cannot
be used for liquid food or
beverages. In the case of liquids
the food preservatives would not
remain on the surface but would
spread through the entire product
and be heavily diluted. The main
applications will therefore be for
fresh meat, meat products and
cheese. And if applied in a strictly
hygienic environment, it may
obviate or reduce the need for
complete preservation of the
foodstuff. The advantage to the
consumer is that they get food
that contains fewer preservatives,
About the Fraunhofer-Gesellschaft
The Fraunhofer-Gesellschaft undertakes applied
research of direct utility to private and public
enterprise and of wide benefit to society. Its
services are solicited by customers and
contractual partners in industry, the service
sector and public administration. The Fraunhofer-
Gesellschaft maintains roughly 80 research units,
including 58 Fraunhofer Institutes, at over 40
different locations throughout Germany. A staff
of some 12,500, predominantly qualified
scientists and engineers, works with an annual
research budget of over one billion euros. Of this
sum, more than 900 million is generated through
contract research. Roughly two thirds of the
Fraunhofer-Gesellschaft’s contract research
revenue is derived from contracts with industry
and from publicly financed research projects. The
remaining one third is contributed by the German
federal and Länder governments, partly as a
means of enabling the institutes to pursue more
fundamental research in areas that are likely to
become relevant to industry and society in five or
ten years’ time. The Fraunhofer-Gesellschaft is
also active on an international level: Affiliated
research centres and representative offices in
Europe, the USA and Asia provide contact with
the regions of greatest importance to present and
future scientific progress and economic
development.
and the industry and retailers
benefit from better shelf life and
quality
Possible future
developments
Future
developments
may include
coating by
spraying to fit
containers.
Also, hydrogen
peroxide treatment is currently
used in packaging materials for
cold sterilisation and aseptic
packaging, but the process does
not seem to be residue-free. It
may be that in the future, antimicrobial
coating could replace
hydrogen treatment. ■
Dr Dieter Sandmeier
Fraunhofer Institute for Process
Engineering and Packaging IVV
www.fraunhofer.de
food spring 2005