Are ready-to-eat salads ready to eat?

We investigated a nationwide outbreak of Salmonella Coeln in Norway, including 26 cases identified between 20 October 2013 and 4 January 2014. We performed a matched case-control study, environmental investigation and detailed traceback of food purchases to identify the source of the outbreak.

lettuce.skull.noroIn the case-control study, cases were found to be more likely than controls to have consumed a ready-to-eat salad mix (matched odds ratio 20, 95% confidence interval 2·7–∞). By traceback of purchases one brand of ready-to-eat salad was indicated, but all environmental samples were negative for Salmonella.

This outbreak underlines that pre-washed and bagged salads carry a risk of infection despite thorough cleaning procedures by the importer. To further reduce the risk of infection by consumption of ready-to-eat salads product quality should be ensured by importers.

Outbreaks linked to salads reinforce the importance of implementation of appropriate food safety management systems, including good practices in lettuce production.

Are ready-to-eat salads ready to eat? An outbreak of Salmonella Coeln linked to imported, mixed, pre-washed and bagged salad, Norway, November 2013

F. Vestrheima1a2 c1, H. Langea1a3, K. Nygårda1, K. Borgena1, A. L. Westera1, M. L. Kvarmea4 and L. Volda1

Epidemiology and Infection, Volume 144, Issue 8, June 2016, pages 1756-1760, DOI: http://dx.doi.org/10.1017/S0950268815002769

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