What type of freezing helps prevent Anisakiasis simplex?

Rapid freezing is the correct choice for preventing Anisakiasis simplex because it quickly brings the temperature of the fish down to levels that can effectively kill the larvae of Anisakis, a parasitic worm. This rapid reduction in temperature typically occurs at -20°C (-4°F) or lower, and ensures that the larvae do not survive in the flesh of the fish, thereby making it safer for consumption.

Slow freezing is less effective because it allows more time for the parasites to remain viable before the temperature drops low enough to ensure lethality. Partial freezing does not adequately eliminate the threat, as it may not sufficiently impact all parts of the fish that could harbor the larvae. Similarly, freezing with salt does not offer the same protective effect since salt brining does not kill the larvae effectively; it may actually just preserve the fish. Rapid freezing stands out as the method that ensures the highest level of safety against Anisakiasis simplex in fish consumption.