Bacterial contamination of lettuce and associated risk factors at production sites, markets and street food restaurants in urban and peri-urban Kumasi, Ghana

Book Title: NA
Year Published: 2010
Month Published: JAN 19
Author: Amponsah-Doku, F. ; Obiri-Danso, K. ; Abaidoo, R. C. ; Andoh, L. A. ; Drechsel, P. ; Kondrasen, F.
Book Group Author: NA

There is increasing evidence that urban grown vegetables in developing countries can be contaminated with pathogenic microorganisms. This is particularly true when wastewater is used in irrigation. The microbiological quality of wastewater grown lettuce on farms, markets and at street food vendor sites were evaluated for thermotolerant coliforms, enterococci and Salmonella using standard methods. Farm irrigation water and market refreshing water (water used in keeping the lettuce fresh) samples were also analysed. Thermotolerant coliforms on lettuce varied from 2.3 x 10(3) to 9.3 x 10(8) on farm, 6.0 x 10(1) to 2.3 x 10(8) on market and 2.3 x 10(6) to 2.4 x 10(9) at street food vendor sites. Indicator bacterial numbers on farm lettuce were higher compared to the irrigation water (1.5 x 10(3) to 4.3 x 10(6)) used on the farms. Thermotolerant coliform numbers in market refreshing water (9.0 x 10(3) to 4.3 x 10(10)) were higher compared to that on the market lettuce. Enterococci numbers on lettuce were lower and ranged from 3.9 x 10(1) to 1.0 x 10(6) on farm, 6.0 x 10(1) to 9.0 x 10(4) on market and 5.1 x 10(3) to 2.5 x 10(6) at street food vendor sites. Salmonella numbers recorded at food vendor sites ranged from 1.5 x 10(1) to 9.3 x 10(2). In general, thermotolerant coliforms numbers increased by 18% while enterococci numbers reduced by 64% from the farms to the street foods. Bacterial counts on farm lettuce and irrigation water, market lettuce and refreshing water and street foods all exceeded the recommended World Health Organization (WHO) and International Commission on Microbiological Specifications for Food (ICMSF) standards of 10(3). Wastewater use on farms and refreshing water in markets could be the main contributors to lettuce contamination and that education on use of effective de-contamination or washing methods before eating will contribute to reducing the risk associated with the consumption of such contaminated foods.

Pages: 217-223
Volume: 5
Number: 2
Journal ISO: Sci. Res. Essays
Organization: NA
ISSN: 1992-2248

Salmonella; irrigation water; thermotolerant coliforms; enterococci; lettuce

Source: Web of Science
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