The Health Protection Agency blames products from major supermarket chains for the recent stomach infection among 300 shoppers.

A survey on 25% of the affected people revealed that 46% of them remembered buying mixed leaf bagged salad from the Morrisons, while 11% ate spinach from the Asda chain.
The agency states that the data is statistically significant and the spinach, which is found in both the products, could be the source of the parasite.
However, both Morrisons and ASDS have denied the claim as the findings were based on statistics and not on testing.
Source-Medindia