Final answer:
Nigiri and sashimi typically feature a variety of fish like salmon and tuna, but eating them raw carries a risk of parasitic infections from agents like Diphyllobothrium species, with undercooked salmon being a common cause in past outbreaks.
Step-by-step explanation:
The typical fish found in nigiri dinner and sashimi samplers/dinner at sushi restaurants can vary, but often include salmon, tuna, yellowtail, mackerel, and octopus. With this popularity, it's important to be aware of health risks. Consuming raw or undercooked fish, especially in dishes like sushi and sashimi, does carry a risk for parasitic infections such as those caused by Diphyllobothrium species, also known as fish tapeworms. These parasites have been linked to cases of infection in places like British Columbia after people consumed undercooked salmon. Despite the relatively low number of reported cases in the United States and Canada, it is presumed many are underreported given the difficulty in recognizing the parasite.