Researchers at Colorado State University are studying ways to improve the microbial stability and shelf life of urwagwa, a banana beer traditionally brewed and consumed in rural Rwanda. Currently, urwagwa has potential food safety issues due to unhygienic traditional brewing methods. The researchers propose using rural electrification projects to power a mobile pasteurization unit, allowing high-temperature, short-time pasteurization of urwagwa. Pasteurization has the potential to kill pathogens like Salmonella and E. coli while extending the shelf life by stopping further fermentation. Future research is needed to test the effectiveness and feasibility of pasteurization treatments and determine any effects on urwagwa's

1. Enhancing the Microbial Stability and Shelf
Life of Rwandan Banana Beer
Trent Moore, Madisen Hodgson, Kyle Joslin
Department of Food Science and Human Nutrition, Colorado State University, Fort Collins, CO
Urwagwa Production ProcessBackground
Bananas grown in rural areas of Rwanda play a huge role as a
dietary staple and source of income for poorer families. Urwagwa
is a brewed “beer” made from bananas and sorghum flour.
Traditionally, urwagwa was consumed during celebrations, rituals,
or social interactions as a cultural symbol. Nowadays, the
beverage is brewed more for income generation in the smaller,
rural areas of Rwanda. Traditional brewing processes pose
potential food safety and shelf life concerns due to unhygienic
practices and poor water quality. A rapidly developing economy in
Rwanda demands higher standards for the production of urwagwa.
Urwagwa Production Process Rural Electrification
Researchers at Colorado State University are working on
developing Smart Village Microgrids; renewable, solar-powered
electric systems designed for rural villages. Rural electrification
could allow for the use of an energy-efficient water bath which
could allow for approximation of high-temperature, low-time
pasteurization. This process is already used to treat milk in other
rural areas. A hold of the urwagwa at 720C for 15 seconds would
replicate common pasteurization techniques. Rapid chilling and
storage in a centralized or personal refrigerator would need to
follow for best practices. It is vital to note training in these
procedures would be required for effectiveness.
Objectives
• Identify critical control points in the traditional process
• Identify common microbial contaminants found throughout the
process and in the final product
• Investigate possible treatments to improve on the microbial
stability of urwagwa
• Provide recommendations on best treatment options
• Suggest future research possibilities and feasibility of
recommended treatments
Critical Control Analysis
References
1. Kuo-Hsiung Tseng, et. al. Advances in Materials Science and Engineering. 2014.
2.Kanyana I., et. al. Journal of Food Technology, 11(2), 38-43.(2013)
3.Shale, K.,et. al. (2014). African Journal of Food Science, 8(7), 376-389.
4.Gaidashova, S. V., et. all. (2005). The International Journal on Banana and Plantain, 2.
5.Byarugaba-Bazirake, G. W. (2008). The effect of enzymatic processing on banana juice and wine (Doctoral
dissertation, Stellenbosch University).
6.Watkins, A. J., et. al. (2008). World Bank Publications.
7.Naicker, M., et al. (2015). Breastfeeding Medicine, 10(2), 107-112.
8.Justine Rayner. et. al. (2013) ACS Sustainable Chemistry & Engineering, 1(7), 737-745
9.Portno, A. D. (1968). Journal of the Institute of Brewing, 74(3), 291-300.
10.Azam-Ali, Sue. (2008). http://answers.practicalaction.org/our-resources/item/banana-beer
11.Asaba, S. (2015, July 5). The New Times.
12.Dianjun Ren, et. al. (2013) Environmental Science and Technology. 47(8), 3825-3832
13.Parawira Wilson, et. al. (2012) Fermentation Technology. 1(3). 1-4
14. All images not cited were obtained from Google Images
Contaminants Found
Water
• Coliforms
Handling/Storage
• Staphylococcus spp.
• Escherichia spp.
• Salmonella spp.
Raw Materials
• Mycotoxins (fumonisin,
• deoxynivalenol, zearalenone)
Clay Water Filtration
Silver ion has been shown to be bactericidal and is found
ubiquitously in the clay native to Rwanda. Personal water filters
constructed out of this clay would reduce total coliform counts in
process water and improve overall quality of the final product.
Fig 1. Justine Rayner et. all. ACS Sustainable Chemistry & Engineering, 2013.
Conclusion
In conclusion, a current experimental electrification project may
provide the catalyst needed to improve the stability of a diet staple
in Rwanda. Electrification in rural villages may allow for the use of a
mobile pasteurization unit. This can be in the form of a laboratory-
style hot water bath with a relatively low energy usage. High-
temperature, short-time pasteurization of urwagwa has the potential
to kill pathogens such as Salmonella spp., Escherichia spp., and
Staphylococcus spp. It can also eliminate spoilage organisms such
as acetic acid bacteria and halt further fermentation from live yeast
species. This would effectively lengthen the shelf life and improve
the food safety of urwagwa. Future research will need to be
conducted to test the effectiveness of these treatments, the
feasibility of implementing them, and the possible flavor impacts
these treatments could have on urwagwa.
Special thanks to Peter Means and Tiffany Weir for providing
important information relevant to the project!
Table 1. Revised from Kanyana I., et. al. Journal of Food Technology, 11(2), 38-43.(2013)