OzFoodNet

Exert from OzFoodNet: quarterly report, 1 January to 31 March 2006

Australian Government Department of Health and Aging

Communicable Diseases Intelligence Volume 30, Number 2, June 2006

 

Exert

Western Australia health authorities completed an investigation into a large outbreak of Salmonella Oranienburg that occurred from November 2005 to February 2006. In total 126 cases were reported as part of the outbreak, compared to an average of 6-12 notifications annually in Western Australia. Initial hypothesis generating questionnaires failed to identify a food vehicle, but the male to female ratio was 1:2. Western Australia conducted a case control study that identified alfalfa sprouts to be strongly associated with illness caused by S. Oranienburg. Brands of alfalfa purchased by the cases were traced back to a single sprout production facility.S. Oranienburg was isolated from alfalfa taken from the residence of cases and at the production facility. The PFGE pattern of isolates from alfalfa sprouts and clinical cases were identical. The company issued a recall of a range of sprout products during February 2006.

Discussion

There was considerable activity during the first quarter of 2006, with overall notifications of Salmonella to the National Notifiable Diseases Surveillance System increased by 14 per cent when compared to the same time frame in the previous two years. There were several multi-jurisdictional investigations into Salmonella and Listeria, including the completion of the investigations into Salmonella Typhimurium 44 and 135 from the previous quarter.1 The reasons for the generalised increase in salmonellosis were unknown, but some of the large ongoing salmonellosis outbreaks in eastern States and Western Australia would have contributed.

The outbreak of Salmonella Oranienburg in Western Australia resulted in a recall of alfalfa sprouts and is the largest reported outbreak of gastroenteritis associated with sprouts in Australia to date. Sprouts are a high risk food that have caused many outbreaks internationally.2 The outbreak has identified a need to review the procedures associated with the growing, harvesting and production of sprouts in Australia. As a result of this outbreak, national food safety policy committees will consider ways to improve food safety for this industry sector.