Cleary et al., report in Eurosurveillance today the preliminary findings of the investigation of an outbreak of foodborne Salmonella Bareilly.

Between August and November 2010, there were 231 laboratory-confirmed reports of S. Bareilly in the United Kingdom. A case–control study showed that consumption of bean sprouts was significantly associated with illness. The investigation concluded that raising public awareness to ensure the correct preparation of raw bean sprouts during cooking was the principal means of preventing further cases.

Bean sprouts follow a complex path from farm to table that includes growing, harvesting, processing and shipping of mung bean seeds, followed by sprouting (normally at temperatures of 20-30 ºC with high humidity) and distribution of the finished product. Seeds may arrive already contaminated or contamination may occur at any point of production and distribution. As in previous outbreaks, this investigation concluded that the seeds were likely to have been contaminated, as investigations at suppliers found little potential for cross contamination of sprouted seeds.

Based on the experience of this investigation, the methodology used for routine microbiological quality control testing of bean sprouts may not be sensitive to low levels of Salmonella contamination. This may have implications for future testing protocols.?The bean sprouts implicated in this investigation were not ready to eat products and would be safe to eat if the instructions for correct preparation (washing and cooking until piping hot) were followed.

I still don’t know what piping hot is.