The high contamination rate we found among blueberries (3/6 samples) may reflect the fact that our sampling procedure was not random.
A hypothesis that blueberries were the source of illness was tested by a case-control study.
Sanitary audit of the orchard revealed multiple opportunities for contamination of blueberries by pickers.
No cases were reported to us by these countries as being associated with blueberry consumption.
In the meantime, as discussed above, the valued concept of a geological approach will remain our solution to the ' blueberry-field ' thought experiment.
Cases whose interviews had led to the formulation of the blueberry hypothesis were included in the study but were not informed of the study hypothesis.
Inquiry about food exposures revealed no dining premises common to a number of cases but suggested consumption of blueberries as a common risk factor.
In response to the outbreak some wholesalers of blueberries have adopted an approved supplier policy whereby only product from producers with approved food safety programmes will be marketed.
