Occurrence of Escherichia coli in Brassica rapa L. chinensis irrigated with low quality water in urban areas of Morogoro, Tanzania

Abstract

Low quality water has become valuable resource with restricted or unrestricted use in food production depending on its quality. This study has quantified the occurrence of Escherichia coli in Brassica rapa L. chinensis (Chinese cabbage) vegetables and low quality irrigation water. A total of 106 samples including Chinese cabbage (69) and water (37) were collected. The E. coli were cultured in petri film selective E. coli plates at 44°C. The Chinese cabbage irrigated with river water at Fungafunga area indicated significantly (P<0.001) high prevalence 86% (n=21, 0.00-4.10 log cfu/g) of E. coli than those irrigated with treated wastewater at Mazimbu 10% (n=48, 0.00-1.36 log cfu/g). The mean counts of E. coli in untreated wastewater ranged from 4.59 to 5.56 log cfu/mL, while in treated wastewater was from 0.54 to 1.05 log cfu/mL and in river water it was 2.40 log cfu/mL. Treated wastewater of the quality found in this study could be used for food production.

Key words: Agricultural irrigation, Chinese cabbage, incidental inputs, river water, wastewater.