Sushi and Parasite Destruction Requirements

By Diane L. Kelsch, MS, REHS

Sushi” refers to a special kind of cooked sticky rice with sweetened rice wine vinegar, but commonly, the term is used to describe a finger-sized piece of raw fish or shellfish on or with a bed of acidified (vinegar) rice.  Although sushi can be made from a wide variety of fish and non fish ingredients, fish products commonly used in sushi include salmon, snapper, tuna, mackerel, yellowtail, roe, sea urchin, eel, clam, conch, scallops, crab, and lobster. 

The larval stage of parasites consumed in raw or undercooked fish can present a health hazard in humans.  Most of these parasites cause mild to moderate illness such as nausea, vomiting, diarrhea, and abdominal pain, but more serious problems such as central nervous system and organ damage can occur.  For that reason, the Food Code requires freezing for parasite destruction in fish that are to be consumed raw or undercooked. 

What are the Food Code requirements for parasite destruction?
The Food Code requires fish that are to be consumed, raw, raw-marinated, partially cooked, or marinated partially-cooked be frozen, for parasite destruction.  The fish must be stored and frozen according to specific time and temperature combinations prior to service or sale in ready-to-eat form:  
(1) Frozen and stored at a -20°C (-4°F) or below for a minimum of 168 hours (7 days) in a freezer;
(2) Frozen at -35°C (-31°F) or below until solid and stored at -35°C (-31°F) or below for a minimum of 15 hours; or (3) Frozen at -35°C (-31°F) or below until solid and stored at -20°C (-4°F) or below for a minimum of 24 hours.

Why is parasite destruction necessary if Table 3.1 of the Fish and Fishery Products Hazards and Controls Guidance does not identify a certain species as having a parasite hazard?
Fish species that do not have specific parasite hazards identified are not necessarily safe when consumed raw or undercooked for the following reasons: Table 3.1 only identifies fish species with well documented parasite hazards, if the fish species is generally cooked before consumption, they are not included in Table 3.1 as having a parasite hazard, and in some cases, there is insufficient information or data to be able to denote a specific parasite hazard or deem the species as naturally parasite-free.   

Therefore, unless the specific species is listed as exempt under Section 3-402.11(B) of the Food Code, the species must undergo freezing for parasite destruction prior to being served in a raw or undercooked state.

What are the Exemptions to Freezing for Parasite Destruction?
Section 3-402.11(B) exempts the following fish or fish products from the freezing requirements: molluscan shellfish, aquacultured fish (such as salmon) that have been raised in net pens, ponds, or tanks and are fed commercially formulated pellet food, fish eggs that have been removed from the skein and rinsed, and the following tuna species, which are naturally parasite free due to their body temperature: Thunnus alalunga, Thunnus albacares (Yellowfin tuna), Thunnus atlanticus, Thunnus maccoyii (Bluefin tuna, Southern), Thunnus obesus (Bigeye tuna), or Thunnus thynnus (Bluefin tuna, Northern

What are the record keeping requirements for parasite destruction?
If the fish is frozen on site, the person in charge shall record the freezing temperature and time to which the fish are subjected. The establishment must be able to verify the freezing requirements established in 3-402.11(A) were met throughout the designated time.

If the fish are frozen by a supplier, a written agreement or statement from the supplier stipulating that the fish supplied are frozen to a temperature and for a time specified under Section 3-402.11(A) may substitute for the record.  Note: A statement from the supplier stating that the fish were processed in a firm that meets the requirements of 21 CFR 123 - Fish and Fishery Products does not meet the record keeping requirement (specific freezing times and temperatures must be provided). 

If the fish are aquacultured and raised and fed as specified in Subparagraph 3-402.11(B)(3), a written agreement or statement from the supplier or aquaculturist stipulating that the fish were raised and fed commercially formulated pellet food shall be obtained by the person in charge.
Records pertaining to parasite destruction must be retained by the establishment for 90 calendar days beyond the time of service or sale of the fish.  

Why does the FDA Food Code Require Parasite Destruction Records be maintained for 90 days?
There are a number of fish parasites that take days, weeks and even months to go through their infective life cycle and exhibit symptoms in the consumer.  This must be followed by a diagnosis, treatment and investigation as to the cause and source of the parasite.  Documentation of freezing fish for parasite destruction was set at 90 days because of the length of time involved with the onset of illness and the investigation of the food source. 

Diane L. Kelsch, MS, REHS is a Regional Retail Food Specialist with the U.S. Public Health Service, U. S. Food and Drug Administration, Southeast Region.