Objectives: To ascertain, using a combination of epidemiological, environmental and microbiological methods of investigation, a possible link between two outbreaks of salmonella food poisoning.
Methods: Case-control studies were carried out on the known at-risk populations. Environmental investigations took place in the food preparation areas used for the social functions and microbiological examinations were carried out on faecal specimens obtained from cases, environmental swabs, and food specimens when these were available.
Results: In both outbreaks, illness was associated with the consumption of sesame prawn toast (outbreak one P<0.004; outbreak two P<0.0001). Salmonella enteritidis phage type 14b was cultured from the faecal specimens of cases in both outbreaks and from a packet of sesame prawn toast used for the second outbreak function. Molecular typing methods indicated that the salmonella cultures obtained in both outbreaks were indistinguishable from each other and from cultures obtained from imported Spanish eggs in a previous survey. Imported Spanish eggs were used in the manufacture of the sesame prawn toast.
Conclusions: Adequate cooking must take place of raw food products, which should be clearly labelled as such. Manufacturers should consider, when possible, the use of pasteurized egg in the preparation of food products.