Microscopic organisms that live within other organisms, namely people or animals, and are spread through contaminated water used in the growing or preparation process of food are referred to as:

Parasites are organisms that live in or on a host, such as a person or animal, and some can spread through contaminated water used in food production or preparation. Protozoa are one kind of parasite, but “parasites” is the broader term that matches the description.

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