Monitoring enterohaemorrhagic Escherichia coli O157:H7 in the vegetable food chain in Ghana

Abstract

The study was carried out to assess the occurrence of Escherichia coli O157:H7 in the vegetable food chain in Accra, the capital city of Ghana. A total of 272 samples of various types of vegetables were screened for Escherichia coli and Escherichia coli O157:H7 using standard microbiological methods. In addition, 80 samples of water used for irrigation, 40 manure soil samples and 250 stool samples of various livestock were also screened. Overall, a total of 243 (37.9%) Escherichia coli isolates were obtained from all the specimens screened. The overall prevalence rates of Escherichia coli for vegetables were 35.3 and 29.4% for external and internal vegetable parts, respectively. The prevalence rates of Escherichia coli for irrigation water, manured soils and livestock faeces were 26.3, 52.5 and 24%, respectively. Overall, only one Escherichia coli isolate from irrigation water was detected to be Escherichia coli O157:H7 which translates to an overall prevalence rate of 0.4% among the Escherichia coli population. The study shows that Escherichia coli O157:H7 is present in the vegetable food chain in Accra but is relatively uncommon. Despite the low prevalence of the organism and its isolation from only irrigation water, the findings of the study call for public health attention owing to the very low infectious dose of Escherichia coli O157:H7 and the common practice of vegetable irrigation. © 2008 Academic Journals Inc.