World Grain - April 2017 - 82

TECHNICAL PROFILE: MILLS FIGHT PATHOGEN MICROORGANISMS

sibility of building sieves containing
an antimicrobial compound that could
prevent mold and bacterial formation.
A fundamental step of the research was
WR¿QGWKHDSSURSULDWHPDWHULDOIRUWKH
sieves that brings together antimicrobial activity and three other main features: compatibility with food usage,
durability and mechanical reliability.
The Ocrim R&D team found a new
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that contains an antimicrobial ingredient
that can be used in milling plants. This
substance is trapped inside the material;
therefore, the antimicrobic is not released
LQWKHÀRXUGXULQJVLIWLQJ7KLVKDVWKHDGvantage of not interfering with the rheological and baking characteristics of the
ÀRXU1RQHWKHOHVVWKHDQWLPLFURELFLVDFtive on the surface of the sieves, blocking
the development of molds and bacteria in
the plansifter. Having a component incorporated in the material means the antimicrobial effect is present and stable for the
whole life of the sieves.
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be active against major human pathogens
like Escherichia coli, Salmonella enteritidis and Staphylococcus aureus, accordLQJWRWKHPRGL¿HG$$7&&PHWKRG
To test the activity range of the comSRXQG2FULPSHUIRUPHG,62
DQG ,62 PHWKRGV 7KH UHVXOWV
show that the new material has a fungistatic effect and that microorganisms are
not able to grow on it. Therefore, the new
sieves are able to stop bacteria and molds
growth inside the plansifters.
In the mill plant, stopping molds proliferation is fundamental for human health.
Mycotoxin-producing fungi are present
on cereals. The development of these
microorganisms can lead to the production of the toxins and subsequent release
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contamination in plansifters can become
a source of mycotoxins contaminations.
To be sure that the new material is effective also against these pathogens, the
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,62 WHVWV XVLQJ WKH VWUDLQV
RI $VSHUJLOOXV ÀDYXV )XVDULXP JUDminearum and Penicilium verrucosum;
82

Microbiological test to compare the new material, right, and the wood multilayer.

WKUHHIXQJLWKDWDUHDEOHWRSURGXFHDÀDWR[LQV%DQG*'21=(1DQGRFKUDtoxin A, respectively. This new material
is active against all of them; therefore,
the sieves are creating a hostile environment against a wide spectrum of microorganisms including the ones that can
produce dangerous mycotoxins.
This research aimed to compare the
new material with the old ones used in
plansifters. Traditionally sieves are built
in wood, but wood can be a substrate for
microorganism growth. Therefore, the
same ISO tests were performed using
round samples of multilayer wood and
composite material placed on a substrate
containing a mixture of bacteria and fungi. As shown in the photo at the top of
the page (microbiological test), after two
weeks of incubation microorganisms are
growing around and on top of the wood
sample (black dots on the left). This demonstrates that if the microenvironment is
optimal, microorganisms can develop on
wood surfaces.
In contrast, in the same experiment performed with the new material, there was
no growth (picture above). This indicates
once again that even when the conditions
are optimal, the antimicrobial material is
able to stop the proliferation of bacterial
and fungi. Accordingly, the substitution
of the old sieves with the new antimicrobial ones can increase mills' barriers
against microorganism contamination.
)LQDOO\WKH5 'WHDPWHVWHGWKHPHchanical characteristics of this composite

material and its suitability to build sieves.
Several tests performed in different milling plants showed that the new sieves
with antimicrobial activity are reliable
and resistant. They can be used in the
VWUHVVIXO VHWWLQJV RI WKH SODQVLIWHUV )XUthermore, the new material combined
with new technological knowhow allows
Ocrim to build sieves in different forms
and for different machines.
The study, conducted in collaboration with the University of Parma, has
led Ocrim to develop a new product to
minimize the formation of new sources of contamination inside the mill and
avoid cross-contaminations between
different batches of cereals. The new
antimicrobial sieves are able to block
bacterial and mold proliferations,
ZLWKRXW DOWHULQJ WKH ÀRXU FKDUDFWHULVtics while maintaining a high quality
standard. Ocrim is using this new antimicrobial composite material to produce sieves for plansifters, but further
research is aimed at utilizing this technology in other strategic areas of the
milling plant in order to increase the
barriers against pathogen microorganisms from the inside the mill.
Simona Digiuni is a post-doctoral researcher
at the Department of Industrial Engineering,
University of Parma, Italy, and Emanuele Bigna
is the plant production manager and R&D
manager, Ocrim s.p.a, Italy.
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April 2017 / World Grain / www.World-Grain.com

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World Grain - April 2017

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