Final answer:
The most common non-fish ingredients in sushi rolls are seaweed and rice. These are foundational elements of sushi, whereas items like avocado and cucumber are additional components. Health risks, such as parasitic infections from raw fish, must be mitigated through proper food safety practices.
Step-by-step explanation:
The two most common non-fish ingredients used in sushi rolls are seaweed and rice. Seaweed, often in the form of nori, wraps the sushi roll, and sushi rice, a specially prepared vinegared rice, forms the base for the roll's structure. While avocado, cucumber, tuna, salmon, soy sauce, and wasabi are also frequently used in sushi, they are additional ingredients that complement the foundational seaweed and rice.
It is important to note that consuming raw fish such as sushi can have health risks, including the potential for parasitic infections like those caused by Diphyllobothrium species, also known as fish tapeworms. Proper handling and preparation of sushi ingredients, including fish, are critical to minimize these risks.