Fresh produce can become contaminated with microscopic parasites when soil, irrigation water, animals, or food-handling practices introduce infectious organisms onto its surface.
One well-known example is Cyclospora, a parasite that has been associated with contaminated fresh produce. Outbreaks have involved various fruits and vegetables, including leafy greens and herbs.
The important point is that contamination is not necessarily visible. A perfectly fresh-looking vegetable can still carry microorganisms.
Wash produce thoroughly under running water before eating it, particularly when it will be consumed raw. Washing does not eliminate every possible hazard, but it can help remove dirt and some contaminants.
5. Raw Aquatic Plants and Freshwater Foods
Certain freshwater plants and aquatic foods can carry parasites when harvested from contaminated environments.
One example is Fasciola, commonly known as the liver fluke. Humans can become infected by consuming raw aquatic plants contaminated with infectious stages of the parasite, particularly in areas where the parasite is endemic.
Watercress and other aquatic vegetation have historically been associated with this type of infection.
This is another reason to be cautious about eating wild plants collected from streams, ponds, or other untreated freshwater environments.
Commercially produced vegetables are generally subject to food-safety controls, but washing and proper preparation remain important.