a1 Department of Public Health Medicine, South Glamorgan Health Authority, Abton House, Wedal Road, Cardiff CF4 3QX
a2 PHLS Communicable Disease Surveillance Centre (Welsh Unit), Abton House, Wedal Road, Cardiff CF4 3QX
a3 Cardiff Public Health Laboratory, University Hospital of Wales, Heath Park, Cardiff CF4 4XW
a4 Cardiff Environmental Services, Wood Street, Cardiff CFI INQ
Two consecutive community outbreaks of Salmonella enteritidis phage type 4 (PT4) traced to the same bakery occurred in Cardiff, Wales during August–September 1992. In the first outbreak, illness was associated with eating custard slices (odds ratio 23·8, 95% confidence interval 6·5–94·4, P < 0·0001), and in the second, with eating fresh cream cakes (odds ratio 15·8, 95% confidence interval 1·6–374, P = 0·004). Environmental investigations implicated cross-contamination during preparation of the cold-custard mix as the cause of the first outbreak, and inadequate cleaning and disinfection of nozzles used for piping cream in the second outbreak. S. enteritidis PT4 was isolated from fresh cream sponge cake retained by a case and from two fresh cream cakes and four environmental swabs obtained at the bakery. This incident illustrates the hazard of widespread environmental contamination with salmonella and the need for thorough environmental cleansing of any premises implicated in an outbreak of food poisoning.
(Accepted September 24 1995)