An outbreak of Salmonella Typhimurium associated with Bakery X franchises in Queensland, Australia.

Background: On the 21st of May 2010, Queensland Health Forensic and Scientific Services identified fourteen cases of Salmonella Typhimurium (STm) infection with the same or similar genotype. Hypothesis-generating interviews identified the consumption of food from BakeryX franchises as a common exposure amongst eight cases.

Methods: A case-control study was conducted to identify the likely source of infection. A case was defined as individuals in whom the outbreak strain of STm was detected from a faecal sample and notified in May 2010. Controls selected were notified cases of other Salmonella strains or Campylobacter with specimen collection dates between 1st 20th May 2010, residing within the same local government area and within the same age group as the case (0-4, 5-19, 20-59, 60 + years). Environmental swabs and food samples from some franchises and the product manufacturer were tested.

Results: A total of 17 cases and 13 controls were enrolled in the study. Eleven of 17 cases reported eating at a BakeryX franchise in the 1-2 days prior to symptom onset. Consuming a pie (any), cake or slice (any) or passionfruit cheesecake was a statistically significant risk factor for infection (p<0.05). No controls identified eating at any BakeryX franchise. Environmental investigation identified the use of unpasteurised eggs in the pastry of the passionfruit cheesecake, and substandard cleanliness and sanitisation of equipment. The egg wash and egg wash container of a franchise were positive for STm but not the outbreak strain.

Conclusions: It is probable that contaminated eggs and inadequate sanitisation resulted in a number foods being implicated in this outbreak. The use of pasteurised eggs and revised sanitisation and cleaning processes were recommended to BakeryX franchises to prevent future outbreaks.

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Author (s): 

Authors: Lisa J. Whop1, 2, 3, RJ. Stafford3, K. Lokuge2 1 OzFoodNet, Communicable Disease Branch, Queensland Health, Queensland, Australia 2 National Centre for Epidemiology and Population Health, The Australian National University, Australian Capital

Presenter (s): 
Ms. Lisa Whop
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