What FDA guideline mandates freezing temperatures for killing parasites like Anisakis roundworms in ocean-dwelling fish?
$-4^{\circ}\text{F}$ for seven days, or $-31^{\circ}\text{F}$ for 15 hours
The process of neutralizing parasites, such as *Anisakis* roundworms often found in wild ocean fish destined for raw preparations like sushi, relies on specific FDA-mandated freezing protocols. These guidelines require the fish flesh to reach a minimum temperature of $-4^{\circ}\text{F}$ and be maintained at that temperature for a full seven days. Alternatively, a much faster but colder blast freezing process is acceptable: maintaining the fish at $-31^{\circ}\text{F}$ for a duration of 15 hours. Successfully achieving and documenting these precise conditions is often difficult to guarantee in standard home freezers, which is why professional sourcing ensures the 'sushi grade' designation for parasite control.
