The UK Health Protection Agency (HPA) has published the findings of its investigation into an outbreak of Cryptosporidium infection that affected at least 300 people in England and Scotland in May 2012.
The HPA investigation found strong evidence of an association between infection and the consumption of one or more types of ready-to-eat pre-cut bagged salad products. An initial link with pre-cut spinach leaves was later found to be less significant. The strongest association was with a mixed salad leaves product from a major supermarket chain.
The investigation was unable to identify the source of the contamination, at least in part because of the short duration of the outbreak. Samples of affected product and microbiological evidence are often no longer available by the time the investigation is initiated.
The investigation report can be accessed here.