Last summer, at the height of the grill-and-salad days a dark cloud loomed. Tainted lettuce , carrying e coli had to be recalled. There was the usual noise to the slow response to a public health hazard. That leads us to think about how the path can be retraced to the source of the trouble. While it may be possible to do so in this country what about produce which is brought in from all corners of the globe? Is this the price we have to pay for being spoilt enough to demand (and get) strawberries in December? This article explains what is being done about it.