petfood pro 4/2021

processing
Goodbye, Salmonella: Bacteria-
Free Through Treatment with
Infrared Light
Food safety is a crucially important issue in
the pet food industry. The EU repeatedly
reports product recalls due to salmonellacontaminated
animal feed, which must
therefore be subjected to thorough
treatments and to inspections to ensure
that they are safe for consumption.
Thermal processes are commonly
used in the food industry to reliably
kill microorganisms. When selecting
the appropriate process, however, it is
important to consider the effects of heat
on the stability of the product to be
treated.
With their patented FoodSafety-IRD
(Infrared Rotary Drum), Kreyenborg,
which specializes in bulk-solids, offers
system components that in addition to
drying and roasting food can sterilize
and pasteurize bulk food or feed with
greater care. Microorganisms such as
salmonellae, E. coli, enterobacteria, mold
or yeast fungi are killed reliably and the
shelf- and storage life of the products are
thus prolonged. This infrared process can
also kill insects and their larvae and eggs
with certainty. Germ reduction achieved
by the FoodSafety-IRD corresponds to a
Log5 validation.
The advantage of the FoodSafety-IRD
lies in the operating principle of infrared
light, conducting energy directly into
the product core, heating the material
from the inside, out. This is unlike other
thermal processes, such as hot air dryers,
which require hours to heat the product,
and does it in reverse – from the outside
to the inside. The FoodSafety-IRD heats
the product core in a matter of minutes,
resulting in significantly shorter dwelltimes.
Working principle: Rotary
motion with infrared-light
technology
The infrared process can be illustrated by
means of a cross-sectional view. The pet
food to be post-processed is continuously
conveyed into the rotary drum by
means of a feeding unit. The product is
transported from the inlet through the
rotary drum to the outlet via a welded-in
helix conveyor and is constantly mixed by
the rotational movement. Simultaneously,
the material is exposed to infrared light,
thus heating entire particles, and when
necessary, water can be sprayed onto the
product. When applied, this fine water
mist has an additional sterilizing function,
since bacteria reduction is enhanced at
the moment of surface evaporation of the
mist. This in addition creates a protective
re-cooling effect. Infrared light has the
advantage of being able to treat even
products with a low water content.
Process preserves color, taste,
consistency and ingredients
The decisive factor for a highly
homogeneous product appearance is
this constant rotation and movement, as
Managing Director Jan Hendrik Ostgathe
explains: "In a belt-dryer, for example,
the product remains in one place for
a longer period of time; this can lead
to uneven nests forming that promote
mold growth. By contrast, the constant
rotational movement inside our infrared
rotary drum dries the material evenly. This
gentle process preserves the color, flavor,
consistency and the valuable ingredients
of the product."
The Foodsafety-IRD has four temperature
zones which can be set independently
according to the product, and which
adjust themselves automatically, based
on the recipe stored in the control
system. The product temperature
remains constant, and overheating
is thus avoided. Depending on the
desired process – in the case of pet food
this would be mainly sterilization and
pasteurization, but drying or roasting,
as for nuts, is also possible – appropriate
product temperature and dwell-time
must be selected. Temperatures of 80 to
200 degrees Celsius and above can be
achieved in the FS-IRD.
Photos: ©Kreyenborg
Cross-sectional view: The rotating drum of the FoodSafety-IRD is constantly in motion,
ensuring uniform exposure to the infrared light.
Stand-alone solution, or
integrated module
Kreyenborg supplies the FoodSafety-IRD
as a plant component for its customers,
but also offers turn-key solutions.
Sterilization and pasteurization usually
involve stand-alone solutions, requiring
the necessary equipment, i.e. upstream
and downstream conveyor technology,
product cooling and big-bag handling
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Technology & Marketing