Registered Dietitian Practice Test

Scombroid and ciguatera fish poisoning are caused by naturally occurring toxins in certain fish rather than by pathogens. The statement that the toxin is not destroyed by proper cooking and freezing is true because these toxins, once formed, are heat-stable and remain in the fish even after cooking. This characteristic distinguishes these types of foodborne illnesses from those caused by bacterial or viral pathogens, which can typically be killed through proper cooking.

For example, scombroid poisoning occurs when fish, particularly species like tuna and mackerel, accumulate high levels of histamine due to improper handling and storage. This histamine is heat-stable and will not break down with temperature changes, leading to potential outbreaks among those consuming the affected fish. Similarly, ciguatera poisoning is linked to the ingestion of fish that have fed on certain toxic microalgae, with the toxins persisting despite cooking methods.

Understanding the stability of these toxins highlights the importance of sourcing seafood from reputable suppliers and following strict handling procedures to minimize the risk of exposure, rather than relying on cooking as a control method.