Ready-to-eat bags of greens may advertise that they have been "thoroughly" or "triple" washed, but that does not guarantee that they are free of bacteria.
And washing it again at home may even add to the risk, as bacteria on hands, utensils or in the sink can contaminate the produce.
There is no complete "kill step" for microbes on leafy greens, because any procedure that would destroy all of the microbes would also damage the vegetables themselves.
The standard process is washing the greens with chlorinated water, but this does not kill 100 percent of microbes, and is often done incorrectly. Between 1998 and 2004, FDA inspection revealed that at as many as a third of domestic and foreign produce farms and packing sheds, the washing was not being performed adequately.
Federal regulations currently require food processors to follow practices that minimize contamination. However, the government only issues very general guidelines on what this entails, so companies have wide play to interpret the meaning.
In digging up what's behind the recent E. coli scare with organic spinach, a disturbing feature in USA Today describes how leafy greens are cleaned before you buy them at the grocery store.
"Triple washing" (which includes two washes with chlorine) is only intended to prevent the spread of bacteria, not to "surface-sanitize" produce. It is no guarantee that your produce will be bacteria-free. And if it's no guarantee, why on earth would you want to drink or possibly eat chlorine?
Research now confirms that cancer-causing agents are created when disinfectant chemicals like chlorine come in contact with organic materials already in water, among them trihalomethanes. Is this really something you want to be putting in your body?
More interesting factoids about the produce you buy at the grocery store and chlorine:
A better option is to locate fruits and vegetables that are grown locally by people you know. While this may be a challenge it is clearly worth the effort and will go a long way toward stopping the factory-farming methods that have been pervasive in producing much of our food.
You can review this recent checklist of sources to help you locate organic farmers in your area.