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 ProjectDuring 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 DesertsFood 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

AflatoxinMesquite 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 HarvestingIn 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.

ConclusionIt 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.