Objectives. To describe an outbreak of food poisoning at a major international sports event in Johannesburg and to determine the likely cause and source of the outbreak.Design. A descriptive, case-control study.Setting. An international sports event in Johannesburg.Methods. A questionnaire survey of involved children was used to conduct a case-control study. Microbiological and chemical analysis of the implicated food was undertaken. Site visits to the premises involved in food preparation were conducted.Results. A total of 578 children were involved. Of the 361 children who returned questionnaires, 134 were affected by an acute-onset emetic-type illness, while 53 children developed diarrhoea. Consumption of fruit juice was associated with acute illness, while diarrhoea was associated with the consumption of maize-meal porridge (pap) and chicken stew. Microbiological analysis revealed high bacterial loads in samples of the fruit juice and the presence of Shigella flexneri in the maize-meal porridge. Visits to the suppliers of the implicated foods revealed several deficiencies in terms of food hygiene precautions.Conclusion. The likely vehicles and causes of this outbreak are elucidated. Guidelines for monitoring the supply and distribution of food to future similar events should be established. Furthermore, hospitals should have protocols in place to deal with such outbreaks in a manner that facilitates epidemiological investigation
