Table of Contents:Table of Contents............................................................................................................................................. 2Abstract................................................................................................................................................................ 3Introduction....................................................................................................................................................... 4Design Objective.............................................................................................................................................. 4Customer Requirements............................................................................................................................... 4Engineering Requirements.......................................................................................................................... 5Benchmarking................................................................................................................................................... 5Design Concepts............................................................................................................................................... 5Design for X........................................................................................................................................................ 5Prototype/Evaluation................................................................................................................................... 5Creativity and Innovation............................................................................................................................ 5Member Contribution.................................................................................................................................... 5Summary and Design Recommendations.............................................................................................. 5References.......................................................................................................................................................... 6
AbstractIt came to our attention as a design team that urine and fecal coliform has been found on
produce in the United States. In recent years, agricultural practices in the United States and
abroad have changed. The recent high volume production practices have led to lackadaisical
supervision of laborers, which has led to the contamination of fruits and vegetables. Ultraviolet
radiation has been found to be effective in the destruction of microbes. Our design team found
that the best solution to the contamination problem would be to allow consumers to disinfect
their produce at home in the crisping drawer of their home refrigerator. The design allows for
the consumer to retrofit our device into the drawer. It will run in forty-five minute intervals for
complete decontamination of the produce.
Introduction:
Several cases throughout the last few decades have shown contamination scares that have
affected anywhere from dozens to thousands. The damage of these contamination scares results
in costly recalls, disease and infection outbreaks, death in the saddest cases. In 2006, E. Coli
contaminated spinach killed one person and sickened over one hundred in California (Clark,
2006). Five years later, a Listeria outbreak in Colorado killed 25 and resulted in a costly recall of
300,000 cases (Neuman, 2011). This January, a Listeria outbreak in 11 states that infected 32
people caused a large Georgia recall on several apple brands, including Granny smiths (Black,
2015). According to the CDC, almost 30,000 illnesses due to foodborne infections were reported
between 2009 and 2010 (Center for Disease Control, 2013). It is quite apparent that the food
industry has a serious problem with microbial infections due to produce. As a design team, we
wanted to find a way to prevent foodborne illnesses without having to install large equipment
within agricultural sectors or making large-scale changes to policy that would take years for the
Food and Drug Administration to process. It became apparent to us that the best way to prevent
illness would be to design a product consumers could use in their own homes that would protect
them from obtaining microbial infections.
One way to prevent microbial infection is to kill microbes on all produce before
consumption. Many people do not actually wash their fruits and vegetable before eating them,
and even if they do, they wash them quickly under water just to remove pesticides. Water is
exactly what a microbe needs in order to colonize anything. Ultraviolet (UV) light is used by
butterflies to detect healthy mates for reproduction (Bybee, 2012). We were inspired by this idea
of using UV light to detect safe from deadly, but we wanted to take a step further and use UV
light to disinfect produce as well.
Based on this, the team decided to create a refrigeration component that could fit within
the crisping bin of a refrigerator in order to sanitize fruits and vegetables. We wanted to
minimize energy use, while encompassing the entire surface of fruits and vegetables within the
drawer. In basic biology classes, we learned that the spacing of a frog’s eyes on the sides and top
of its head allows it to see 360 degrees around its body. Using this concept and the idea of
refracting and reflecting light, the frogger disinfector was born!
Design Objective The objective of this design was to create an affordable, dependable, effective device that
succeeded in conveniently disinfecting bacteria from produce that lies within a residential
refrigerator drawer. The requirements of this design process also required completion of the final
product (or working prototype) with a time frame of approximately four weeks. In order to
complete the entire design process, final report, video, and presentation in such a limited time
span, an organized chart such as a Gantt Chart, was essential to keep the design team on track to
finish the project. The figure below (Figure 1) depicts the tasks required, durations of those task,
and at what time those task should be complete.
Figure 1: Gantt Chart of Intended Task
Customer Requirements The main requirements from the customer was that the design would decontaminate produce in a reasonable amount of time as well as be safe for daily use. Other important factors included an easy-to-use apparatus that was not bulky or cumbersome, and a design that allowed for easy installation into any standard refrigerator drawer. The customers wanted a device that would be low-maintenance, energy efficient, and have a substantial battery life.
Engineering Requirements For disinfection purposes it was required that we used an ultraviolet light with a wavelength of 250 to 270 nanometers. The maximum rate of power consumption needed to be less than 40 Watts. The design also had to be able to fit inside the drawer of the refrigerator and allow ample space for produce storage as well as even ultraviolet radiation distribution. This constrained the design to occupy a volume of no more than 48 cubic inches. For ease of use and installation, the time required to install the device and then operate needed to be less than 5 minutes. And the time for maintenance of the apparatus, which included cleaning the device, changing drained batteries and/or defective LEDs needed to be less than 10 minutes.
BenchmarkingIn the process of researching common techniques and existing products that have already
been designed to disinfect a medium with the use of ultraviolet light waves, our team took note
of a few products and compared them to our own idea. This process of identifying and evaluating
competition based off of the customers requirements is known as benchmarking. This task brings
awareness of what already exist in the market, and how those products compare to our intended
design. Two products have been used to benchmark our design and can be also be referenced in
our Quality Function Deployment chart. These products include a pulse UV light cleaning
system that farmers would use to clean pathogens from their potato crops (see Figure 2) ,and a
UV water and surface disinfector made by sharper image. Both items are actually quite different
than our intended design, and make our product somewhat unique in it’s intended use. The
benchmarking process can be seen in more detail in the QFD chart below. Our team compared
our design customer requirements to our benchmark products in categories such as ability to
disinfect produce, the time taken to accomplish the disinfection, cost, size or bulkiness of the
product, life span or battery life, aesthetics, and energy consumption. These same qualities were
compared to the design that our team envisioned, and found that compared to the other
benchmarks our product satisfied the preferred requirements more so than the other products on
average.
Figure 2: Benchmark Company 1 - Agricultural UV Disinfection
Figure 3: Benchmark Company 2 - Sharper Image Water and
Surface Disinfector
Design Concepts
Our team discussed and brainstormed many concepts and designs that were intended to
accomplish bacteria disinfection within refrigeration drawers. Each member sketched and
discussed their own design, no matter how wild or far fetched they might have been, and
bounced ideas off of each other to spark imagination of our final design. It was through these
discussions that ball- in- socket joints, matted LED pads attached to all four walls, reflective
lighting principles, and many more concepts were discussed. After looking to nature for inspired
design techniques to maximize light coverage efficiency, the eyes of a frog were investigated.
Frog eyes are unique in the fact that they have a 360 degree line of sight. Our team wanted to be
able to use minimal LED lenses to reflect the maximum amount of low wavelength light for
disinfection.
Design for X
Cost:
When designing our finalized product, we managed the overall cost as effectively as
possible. The UV light that emits the necessary wavelengths is one of the more costly parts of the
product. However, we did cut down the cost by designing our product so that the user would not
have to go buy a whole new refrigerator or new drawers but simply a quick installation of our
product and protective, reflective inserts for the sides of the drawers. The reflective surfaces are
not costly. The reflective surfaces provide an all area coverage so we could cut down on the
number of bulbs used as well as the size of the bulbs. Our product now runs on simple batteries
so this aspect of the maintenance costs would be on the low end of the scale. Although, our end
goal for the actual product, outside of the prototype, would be to include an arduino to turn the
device on and off without having a physical switch on the drawer. A basic arduino would not add
too much to the overall cost of the product and their lifespan is typically long, therefore, the
maintenance costs would be low as well. Our group definitely took the cost into thought when
designing our product so the everyday user could benefit from our product.
Safety:
Our team took careful consideration into designing a product that is safe for everyday
use. We include many aspects in our design in order to address this very important aspect*.
Since we are using certain wavelengths of UV light that are more dangerous than regular UV
light, such as rays emitted from the sun, exposure for prolonged periods of time can cause harm
to the user so we had to take extra precautions in the safety department due to this. One of the
ways we prevented exposure was to make sure that the user did not have to manually turn the
light on and risk possibly being exposed to the rays. In our prototype, we have an outside switch
at the moment, but in our end product we want to include an arduino where the user could turn
on the device without even opening the refrigerator. The use of an arduino would greatly cut
down the safety costs of our product. Both the switch and the arduino include a timer for how
long the device would be on to ensure full decontamination; this aspect will also cut down on the
exposure to the light since the user would not have to manually turn the light off and it would
prevent overexposure of UV rays to the produce. Also, we include a protective coating within the
drawer that will block the rays from penetrating through the drawer into unwanted areas of the
refrigerator affecting other food and the user. This coating, which is also reflective, will allow
the user to use the refrigerator when the device is on without having to worry about being
exposed themselves or the other food being exposed to the rays. The reflective coating inside
will allow the lights to hit every angle of the produce that are being decontaminated to ensure
that the entire object is covered by the rays not just the top, making it even more safe for the user
to consume. Since we are dealing with harmful UV rays, we took every measure to ensure safety
in our product so our consumers would want to buy our product and use it in the future.
Sustainability:
Currently, sustainability is on the minds of most designers. We took into careful
consideration the effect we would have on the environment and if our product could be made
with sustainable resources. We found that we could easily design a product with sustainable
practices in mind. Our design contributes to sustainable living by eliminating the need to use
water to wash produce. This could prove to be especially useful in California where water is
scarce and the produce industry is so large. If there was a demand, our design could be suited for
commercial use by expanding the size of our product. Water is also used extensively in energy
production, so it was important for us to consider the energy usage required to properly operate
our ultraviolet light component. The power consumption of our device is minimal and may be
fabricated using biomaterials or recycled plastics.
Impact on the Environment and Society:
In the past decade, there have been many widely publicized cases of E. Coli and
Salmonella outbreaks with produce. Many times these outbreaks led to deaths and serious illness
requiring hospitalization. The sole inspiration for our design was to protect people from a
preventable illness. The risk of contracting a foodborne illness is reduced when using our
product properly, which greatly affects public health and society in a positive way. The impact
on the environment is attributed to the reduction of spoilage by eliminating the microbes that
increase the rate of spoilage. By reducing spoilage, there is less waste and less reason to grow
more than we need. With safe produce on the market, fruit and vegetable consumption could
increase, which would improve the diets and overall health of many people.
Prototype/Evaluation:
Figure 4: Quality Function Deployment
Developing the prototype for this design meant first understanding the requirements that the
customers and stakeholders desired. To translate non specific customer requirements into
quantifiable engineering specification, a quality function deployment was carried out (see Figure
4). It was through this process that our team began to understand what should be designed and
what was to be expected of the design. Taking these engineering requirements and our “Design
for X” variables into consideration, our team designed and created a prototype that would model
our final manufactured product. Prototype generation began with many penciled sketched and
discussion with our team. Our team determined we would utilize the technology of 3-D printing
that the University of Georgia College of Engineering provided. The Frogger device was created
in the AutoCAD and transmitted to a STL file the could be processed and produced by the 3-D
printer. After the case of the prototype was formed, our LED lights and circuitry was installed.
Switched were installed to each of the LED batteries so that the devices could be turned off and
on. Obviously what was created was a simplified model that was created to provide proof of our
concept. For example, our device would contain Arduino Uno that we would be coded to create a
timing effect after the switch was clicked to turn off and on. The following figures demonstrate
our final prototype:
Figure 6: Final Constructed Prototype
Creativity and Innovation
We wanted to obtain the highest possible surface coverage for our ultraviolet light
distribution. After discussion and brainstorming, we found inspiration in the way frog’s eyes
work. Because of the positioning and design of a frog’s eyes, they are able to have nearly a 360
degree view (Deyton). To aid in the light distribution modeled after a frog’s eyes, we elected to
make all of the surfaces of the refrigerator drawer highly reflective. The initial inspiration for
the implementation of ultraviolet radiation in our design came from an interest in ultraviolet light
sparked by how butterflies use ultraviolet light. Butterflies have special photoreceptors that
allow them to reflect and absorb UV to communicate without alerting predators and find nectar
(Bybee, 2012).
Member Contribution
Each member of our design team played a valuable role in the entire process of
developing our product. Our team was well comprised of students from all degree programs
including Agricultural Engineering (Natural Resources and Mechanical emphasis), Biological
Engineering, and Biomedical Engineering. This diversity proved to be very beneficial in that
each person had certain gifts and education backgrounds that they could contribute to the design
of our device. Each of the tasks that were displayed in our Gantt Chart (see Figure 1), and many
more were divided and conquered fairly between each group member. Members volunteered to
take on a task based on what they felt most confident in completing. Much of our brainstorming,
concept generation, research, assembly of the prototype, and the report was completed as a team,
but there were individual tasks that were carried out by particular team members. The following
list was created to demonstrate individual member contributions to the overall design project:
Richard Dozier : Head responsibility for the report, Assisted in the formation of the final
report and presentation, creation of QFD diagram, creation of Gantt chart, and
benchmarking research.
Jenna Alsaleh : Contribution to prototype creation, part of the design team, co-prototype
creator with Crystal, assistant to Chris in powerpoint presentation, providing of funds for
materials, Introduction writer, responsible for keeping up with the design notebook.
Katie Homeyer : Part of the design team and Co-owner of original concept idea alongside
Crystal, Providing of funds for materials, assistant writer of the report.
Troupe Tabb : Co-writer of the final report and research alongside Trey, Pursuit of
materials for the final product, responsible for obtaining customer and engineering
requirements.
Crystal Schreck : Co-owner of original concept idea alongside Katie, Assisted in product
design, prototype creation, and background research, as well as creation of informational
video.
Chris Lenear : Head designer and main creator of the powerpoint presentation, part of the
design team for the prototype creation.
Summary and Design Recommendations
Our product, cooperatively created by this design team, has great potential to impact
people’s health, the food system, and the environment. The Frogger Disinfector will primarily be
used to disinfect fresh produce, the most common source of food poisoning, in a much more
convenient way. This will cut down on food-born illnesses in the general population and help to
keep food from spoiling. If produce is less likely to cause illness and is capable of lasting longer
in the refrigerator, people will be more likely to eat more vegetables, leading to a healthier diet.
This will also reduce the amount of food that is wasted as a result of spoilage meaning that less
money will be wasted on groceries. If less food is thrown away, farmers can grow vegetables and
fruits in a conservative and efficient manner. It is clear this product can be a critical
improvement to many aspects of the food process.
With the great potential of this product, it deserves to be continuously improved upon. At
this time, we can recommend improving this product in only a few ways. An Arduino should be
installed to conserve energy and ensure the safety of the customer. This could make sure that no
energy is wasted running the light when it does not need to be on. Because exposure to UV
radiation is harmful, an Arduino micro-controller should be designed so that the light turns off
anytime the drawer is opened. Another improvement would involve finding an optimal angle to
position the case so that the UV rays have a better chance of covering every piece of produce in
the drawer, no matter where it is positioned or how full the drawer is.
Even more improvements can and should be added to this list. It may be impossible to
find a perfect design, but we can strive for perfection anyway to create the best product we can.
Works Cited
Black, Gary W. Consumers advised not to eat certain apples and pre-packaged caramel
apples due to foodborne illness outbreak. Press Release . Atlanta: Georgia Department of
Agriculture , 2015. Web.
Bybee, Seth M., et al. "UV Photoreceptors And UV-Yellow Wing Pigments In Heliconius
Butterflies Allow A Color Signal To Serve Both Mimicry And Intraspecific Communication."
