In the United States, digestive system infections caused by the parasite Cyclospora are increasing. The outbreak has been associated with spinach lettuce produced in Mexico and distributed nationwide. The parasite spreads through water or food contaminated with feces and completes its life cycle in the human intestines. It does not spread from person to person; each outbreak is traced back to a contaminated food or water source.
The risk of finding this parasite in pre-packaged salad products is high because these products are typically consumed raw and can become contaminated at multiple stages during production. Scientists recommend choosing vegetables with peels or smooth surfaces, such as tomatoes and cucumbers. Washing the entire spinach lettuce, discarding outer leaves, and thoroughly cleaning the inner parts may reduce some risk, but washing or disinfectants cannot completely eliminate the parasite's protective casing.
The only effective method to kill Cyclospora is heat. Food must be cooked to at least 70°C (158°F). The U.S. Department of Health recommends washing all fruits and vegetables under running water, scrubbing hard vegetables with a brush, and cutting away damaged parts.