Microbial risk assessment and health concern of vegetables irrigated with Akaki River in Addis Ababa, Ethiopia

Background: The consumption of vegetables is increasing in Ethiopia because of their high health benefits. Smallholder farmers who use water from the Akaki River for irrigation meet more than 60% of the vegetable needs of Addis Ababa. However, the Akaki River is severely polluted by anthropogenic impacts. Hence, the intake of vegetables grown in fecally contaminated water can lead to many health problems. Therefore, this study aimed to evaluate microbial contamination of irrigation water and vegetables in Addis Ababa. Methods: This study assessed the quality of water and vegetables collected from the Akaki River. Fresh vegetables, such as Ethiopian kale, lettuce, cabbage, and spinach, were col-lected from 14 farmlands during the dry and wet seasons. The analysis of E. coli non-E. coli, total coliform (TC), fecal coliform (FC), and total aerobic plate count (TAC) were deter-mined using standard methods. Results: The findings of this study indicated that all fresh vegetables were contaminated with total coliforms, fecal coliforms, and total aerobic plate counts in both dry and wet seasons. The overall mean counts of E. coli and non-E. coli in the water samples were 2.09 and > 3.48 log10 CFU 10 mL -1, respectively. The mean counts of TC, FC, and TAC on the sampled vegetables were 3.22, 1.37, and 4.72 in the dry season, and 3.87, 2.57, and 5.09 log10 CFU per gram in the wet season, respectively. Conclusion: The Akaki River has been contaminated with non-E. Coli & E. coli coliforms, and did not meet the WHO guideline criteria for safe irrigation. The microbial contami-nation of vegetables was found to be high and exceeded the hazard analysis and critical control points for total quality management (HACCPTQM) and International Commission on Microbiological Specifications for Food (ICMSF) limits for safe consumption. Therefore, the local government is responsible for ensuring that farmers can use pollution-reducing irrigation systems and that consumers are aware of the health risks of contaminated veg-etables and take appropriate precautions.(c) 2022 The Author(s). Published by Elsevier B.V. on behalf of African Institute of Mathematical Sciences / Next Einstein Initiative. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )