Foodborne illness is a major international health problem and an important cause of reduced economic growth (1). There is concern about, for example, chemical contamination, Escherichia coli O157:H7 infections, the use of antibiotics in animal rearing and the transfer of antibiotic resistance to human pathogens (2).
The problems of food safety in the industrialized world differ considerably from those faced by developing countries. Whereas traditional methods are used for marketing fresh produce in the latter countries, food processing and packaging are the norm in industrialized countries. In developing countries a large proportion of ready-to-eat food is sold on the streets. Table 1 shows some of the foods sold on the streets in Ghana.
The term "street food" refers to a wide variety of ready-to-eat foods and beverages sold, and sometimes prepared, in public places. As with fast food, the final preparation occurs when meals are ordered by customers. Street food may be consumed where it is purchased or can be taken away and eaten elsewhere.
The consumption of street food is common in many countries where unemployment is high, salaries are low, work opportunities and social programmes are limited, and where urbanization is taking place. Street food vendors benefit from a positive cash flow, often evade taxation, and can determine their own working hours. In selling snacks, complete meals, and refreshments at relatively low prices, they provide an essential service to workers, shoppers, travellers, and people on low incomes. People who depend on such food are often more interested in its convenience than in questions of its safety, quality and hygiene.
The hygienic aspects of vending operations are a major source of concern for food control officers. For example, stands are often crude structures, and running water may not be readily available. Also toilets and adequate washing facilities are rarely available. The washing of hands, utensils, and dishes is often done in buckets or bowls. Disinfection is not usually carried out, and insects and rodents may be attracted to sites where there is no organized sewage disposal. Finally food is not adequately protected from flies and refrigeration is usually unavailable.
We have previously studied risk factors for acute and persistent diarrhoea in an urban slum in Accra, Ghana (3). About 60% of 951 mothers supplemented their children's diet with street food. The children had an increased risk of both acute and persistent diarrhoea. There were higher levels of contamination in the street food given to these children than in food cooked at home. In the same area we evaluated also the following: the role of street food vendors in the transmission of diarrhoeal pathogens; the microbial quality of street foods; and factors that could predispose food to contamination with bacteria.
We have already published data on the role of street food vendors in the transmission of diarrhoeal pathogens (4). In the present paper we report our findings on the microbial quality of street foods and the risk factors for food contamination.
Prior to starting the investigation, we explained its aims to head teachers and representatives of the food vendors in the study area. The street food vendors were recruited into the study after the owners of the vending sites had given their approval and the vendors were assured total confidentiality.
Study population and sample collection
The study was conducted in Nima-Kotobabi-Pig Farm-Accra New Town sub-area. Vendors of street foods in the major streets, markets and two schools were recruited. There were approximately 120 vending sites; the persons in charge of the vending points (subsequently referred to as the vendors) were the main subjects of study. A structured questionnaire was used to gather data on vital statistics, personal and food hygiene practices and knowledge of foodborne pathogens. …