Classical food technologists would have laughed if they were told that fresh produce like lettuce, spinach etc could be carriers of pathogenic bacteria like Salmonella, as meat and poultry have been the popular candidates for such contamination. But during the last few years, with the salad eating habits gaining ground, fresh produce, both cut as well as whole have been causing innumerable incidences of food poisoning in some of the developed countries. What is alarming is that even chlorine washing during processing and packing, some times, fails to decontaminate the products. Consumers are highly vulnerable because they assume that the packed produce on the shelves of the super markets have been safety checked by the processors.
How can these produce grown under protected environment can get contaminated with pathogenic bacteria? "Greens are especially vulnerable for several reasons, including that they are grown so close to the ground -- unlike, say, fruit from trees -- and can be tainted by water runoff, a persistent source of contamination when it carries animal waste. What makes fresh-cut greens more susceptible is also what makes them convenient: the cutting and bagging that eliminate much of the work of salad preparation. That processing allows pathogens to get into the leaves, where they can flourish. The machinery used and the mixing of greens from various farms contribute to those dangers, not unlike the risks associated with processing ground beef".
In India the salad eating habit has not yet been popular and no imminent threat can be anticipated on this count. Traditionally Indian consumers do eat freshly washed and cut vegetables like cucumber, onion and tomato. Both onion and cucumber are peeled reducing the danger while tomato can still pose some risk. Probably it may take years for such a threat perception becoming a reality though this area needs careful watching, especially in urban areas where fresh produce are brought from sub-urban farms, growing vegetables using sullage water. Practice of washing is never followed especially by the farmers and the produce arrive straight at the market, leaving the onus on the consumer to make them safe at home. Advent of organized retailing probably may change the scenario as they have a reputation to protect and therefore may follow scientific practices to make fresh produce safer.