AUGUST n SEPTEMBER 2018 17
at a lower cost of production and their
lifetime increases, they will begin to
replace existing UV-C lamps as a cost-effective, environmentally friendly
alternative to save energy and improve
safety and shelf life of produced foods
from field to fork.
Flexibility of Applications for
Experiments and Processing
Multiple-wavelength UV LED chips
have great potential for use in bench-
top-scale validation experiments. Their
small size means they can be easily inte-
grated into a collimated beam apparatus
for the purpose of studying microbial
inactivation kinetics at multiple wave-
lengths and wavelength optimization
on surfaces and in liquid solutions.
The UV LED collimated beam unit
(Figure 3) was used to select the optimal
inactivation wavelengths against three
food pathogenic organisms and find
appropriate nonpathogenic surrogates.
This unit consisted of an array contain-
ing three LEDs of each wavelength with
thermal management, collimated tube,
stand, and Petri dish, which allows test-
ing in controlled conditions and mea-
sured UV exposure.
The selected LED chips can then be
used in customized devices at higher
irradiance to scale up disinfection
processes by establishing the operating
UV doses for specific product applica-
tions and intended technical effects.
An example of a UV disinfection box
that allows treating whole fresh produce
samples is shown in Figure 4. It also can
be used for the purposes of the process
validation and studies of the effects of
product- and process-critical parameters.
UV-C LED chips enable flexible
modular design over rigid lamps and
their required bulky ballasts. UV-C
LEDs can easily be incorporated into
simple water filters, providing a highly
Figure 2. Relationship between UV LED wavelength, irradiance, and log count reduction of E.
coli O157:H7 using UV LEDs between 259 and 365 nm and an equivalent UV dose of
255 275 295 315 335 355
UV treatment wavelength (nm)
Figure 3. UV LED Collimated Beam Unit
(continued on page 64)
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