Among other natural items that are dangerous, Salmonella bacteria rank high on the list. Consuming foods contaminated with this bug can be life-threatening — especially for the young, the old, and people with compromised immune systems. While we often think of meats when considering the sources of food-borne illnesses, fruits and vegetables are also on the list.
Consider the recent outbreak of Salmonella linked to a particular brand of Mexican papayas — the yellow Maridol papaya distributed by the Grande Produce company. According to an article in The New York Times, one person has died and 46 others have been sickened in this outbreak that has affected people in 13 states.
Within about 8 to 72 hours after consumption, Salmonella infection can result in fever, diarrhea and abdominal cramps. If the diarrhea is severe it can cause life-threatening dehydration.
It's likely the bacteria were on the outside of the fruit and were carried to the edible portion when it was cut before consumption. If that were the case, then careful washing might have prevented the illnesses.
Another means of preventing such outbreaks is the much-maligned food irradiation. Food irradiation does not make food radioactive, and leaves nothing behind except dead bacteria. Unfortunately, our misled society has an unwonted fear of the process, and thus a potential level of protection is not available. Of course, irradiated fruits could always be re-contaminated after such treatment, however it seems most likely that the affected papaya were contaminated before being shipped to sales points. Information on food irradiation is available in the ACSH booklet here. And more information about avoiding foodborne illness can be found here.
For those who insist that "natural" is always best, this recent outbreak should lead them to reconsider their stance.