harvesting mesquite flour at the university of arizona: a case study in local innovative food...
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Harvesting Mesquite Flour at the University of Arizona:A Case Study in Local Innovative Food Production
Bachelor of Science inMentor: Melanie Lenart, Ph.D. Elondra Ome Eichenberger Sustainable Built Environments
The UA Mesquite Project
During the summer season, mesquite trees produce large quantities
of bean pods that can be harvested and milled into flour. The UA
Office of Sustainability collaborated with the Union Dining Services in
2011 to manage a small harvesting system on campus. The beans
collected were milled into flour and used to make certain foods in the
University of Arizona Main Kitchen. A proposal was submitted to the
Green Fund and the mesquite project became a funded sustainability
project at the university from 2011-2013.
Pods after collection Elondra doing a pod quality check
Example of good quality pods Mesquite brownie sold at UA Canyon Café Photo courtesy: Megan Kimble, UA Office of Sustainability
Food Deserts
Food deserts are areas that are considered to have limited access to
affordable and nutritious food. This last year, Tucson, Arizona remains
to have numerous patches of food deserts. The graph below shows
highlighted patches that are considered food deserts.
Map taken from Agricultural Marketing Service
Promoting harvesting in the community is a small step towards action.
The mesquite project helped teach people how to live based off what
is already placed on the natural surrounding landscape.
Best PracticesWith the help of Dr. Cotty and his Aflatoxin science lab located at the UA, a safe
harvesting method was drafted and approved by UA Risk Management:
1. No pods collected from the ground for the manufacture of mesquite flour to avoid contamination.
2. Examine for insect damage, and those displaying beetle entrance and exit holes are discarded.
3. Dry and store in airtight containers. Maintaining the moisture of the pods at or less than 10% total weight.
4. Milling of the flour takes place after monsoon season has ended.
5. Process pods in lower humidity to produce flour with lower moisture content and therefore a lower risk of A. flavus growth and aflatoxin contamination.
Volunteers laying tarps under tree Weighing and calculating moisture content
Photo courtesy: Megan Kimble, UA Office of Sustainability
Aflatoxin
Mesquite pods that are produced for edible consumption has a risk of being highly
unsafe, due to a fungus that naturally grows on mesquite pods called Aspergillus. This
fungus can produce a toxin called Aflatoxin. It is extremely important to never
consume a product that has come from a mesquite pod with evidence of mold. Insect
damage on the mesquite pods are major determining factors in mold infestation and
possible toxin production. Some pods can have many small, circular bruchid beetle
holes. Side effects of Aflatoxin consumption include liver cancer, vomiting, abdominal
pain, development growth effects in children, and death
Volunteer checking for insect damage Insect damaged pods
Photo courtesy: Megan Kimble, UA Office of Sustainability
Passive Harvesting
In Summer 2012, Levi Buggenum, a UA Architecture Student, was
hired to design a net system to collect mesquite pods. Volunteers
were hard to come by during the summer harvests and yields were
very low. Therefore, there was hope that this experiment would be
the solution towards collecting a higher yield of mesquite pods.
Designs and photo by Levi Buggenum
After Levi designed an inexpensive net system, community members
who practiced mesquite harvesting were asked to use the net design
for the harvesting season of Summer 2013. Many results showed that
the pods were not maintaining inside the net. This passive harvesting
experiment did not succeed.
Conclusion
It is predicted by the UA Dining Services that they need no less than
50 pounds of flour for each season to make the mesquite project a
sustained organization. During the 2011-2013 season, no more than
13 pounds of flour were produced each summer. Because of the
continuous small yields, the project had to end in 2013 and will
remain a resource for research in other projects.