The Open Food Science Journal, 2007, 1, 1-5 1 1874-2564/07 2007 Bentham Science Publishers Ltd. Risk of Exposure to Marketed Milk with Antimicrobial Drug Residues in Ghana K.G. Aning 1 , E.S. Donkor *,1,4 , A. Omore 2 , G.K. Nurah 3 , E.L.K. Osafo 3 and S. Staal 2 1 Animal Research Institute, Council for Scientific and Industrial Research, Achimota, Ghana 2 International Livestock Research Institute, Nairobi, Kenya 3 Faculty of Agriculture, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana 4 Department of Microbiology, University of Ghana Medical School, College of Health Sciences, Accra, Ghana Abstract: The study was carried out to determine the extent to which antimicrobial drugs may be translocated into milk and the associated risk of exposure by consumers. A total of 394 milk samples were collected in the study sites in dry and wet seasons, and from different categories of milk market agents, including producers (farmers), processors, wholesalers (assemblers) and retailers. The milk samples were screened for antimicrobial drug residues using the Charm Aim-96 an- timicrobial inhibition assay screening kit. Overall, 35.5% (140/394) of the milk samples collected were contaminated with one or more of the antimicrobial drugs screened. This translates into an average risk of exposure every third time a con- sumer drinks locally produced milk. There was no significant difference in contamination levels between season and area of sampling. Among market agents, contamination levels ranged from 16.6% (9/54) for wholesalers or milk assemblers to 54.2% (13/24) for milk processors. There were no significant differences in prevalence proportions of drug residues in milk from different types of traders between and within locations. INTRODUCTION Dairying is a young and developing industry in Ghana that can potentially create many more employment and in- come-generating opportunities in rural and urban areas than is currently the case. Up to now, a large proportion of milk consumption is derived from imported milk products. This is partly because many consumers consider the locally pro- duced milk to be generally of low quality or unsafe due to various documented and undocumented reasons. Docu- mented health risks mainly relate to microbial hazards and poor quality of milk produced locally [1, 2]. However, risks related to antimicrobial drugs remain largely unknown. Various antimicrobial agents used in the treatment of animal diseases have been shown to occur in milk and other animal products used as food by humans. Although antimi- crobial drugs are useful for treatment of human infections, their occurrence in milk causes adverse public health effects such as drug resistance and hypersensitivity that could be life threatening [3]. A significant proportion of humans are at risk. For example, about 3.4% of the human population is sensitive to sulfonamides [4], one of the antimicrobial agents screened in this study. To protect the public against possible health risks caused by such hazards, regulations regarding veterinary use of drugs, including withholding periods after antimicrobial therapy, have been formulated. However, such regulations are not usually adhered to, especially in developing countries [5]. Consequently, undesirable exposure to antimicrobial drug residues tends to be higher in developing countries than *Address correspondence to this author at the Department of Microbiology, University of Ghana Medical School, College of Health Sciences, Accra, Ghana; E-mail: ericsdon@hotmail.com elsewhere. This study was carried out to determine the oc- currence of antimicrobial drug residues in marketed milk in Ghana and to estimate the exposure by milk consumers to the residues. MATERIALS AND METHODS Study Area and Sampling The study was carried out at two sites namely, the peri- urban areas of Accra and Kumasi, the two cities in Ghana (Fig. 1). The areas were selected to represent a variation in consumer concentration, market access, and dairy production intensity. Accra, which has a higher population density, was chosen to represent high market access and relatively more intensive dairy production compared to Kumasi that has a lower population density, medium market access and more extensive dairy production systems around it. The study was carried out in two steps. First, Participa- tory Rural Appraisals (PRAs) were conducted among con- sumers, marketing agents and producer-sellers at each study site at the beginning of the research to identify consumer preferences and practices, types of marketed dairy products, major marketing pathways, points and milk handling prac- tices by market agents. In the second step, the information obtained during the PRAs was used to construct a structured questionnaire and to select locations for field surveys in specific areas considered by key informants to have dairy marketing as an important activity. In and around both cities, data were collected in these locations by questionnaire from randomly selected milk traders during the dry (December 1999 - March 2000 in Kumasi area and March – June 2000 in Accra area) and wet (July – September 2000 in Kumasi area and July – October 2000 in Accra area) seasons. Respondents comprised differ- ent categories of market agents including producers (some of