An Outbreak of Salmonella Typhimurium Phage Type 64 Gastroenteritis Linked to Catered Luncheons in Adelaide, South Australia, June 2005

Abstract

Salmonella sp. are important causes of foodborne illness, with restaurants and catered functions being commonly reported settings for outbreaks. In June 2005 an investigation commenced following reports of gastrointestinal illness in attendees at luncheons catered by an Adelaide café, as well as persons eating at the café itself. The investigation sought to determine the existence of an outbreak, identify a source and method of transmission and implement public health measures to prevent further cases. Lists of luncheon attendees were obtained from function organisers. A retrospective cohort study was commenced using a structured questionnaire developed from the café's menu listings. A suspected case was defined as a person developing two or more gastrointestinal symptoms after attending a luncheon catered by the café. A case series investigation was used for café diners. Of the 102 respondents, 61 (60%) met the case definition with 32 subsequently confirmed as Salmonella Typhimurium phage type 64 (STM 64) infections. Of the 61 cases, 59 (96%) reported eating a bread roll. STM 64 was detected in raw defrosted chicken recovered from the café's kitchen. This suggested cross-contamination from the chicken to one or more ingredients common to the bread rolls was the route of infection. To prevent further cases, perishable goods were discarded, the café was closed, the premises cleaned, then restrictions were placed on the types of foods served. This investigation's findings highlight the importance of safe food handling and hand hygiene in commercial food preparation.