704 Modern Food Microbiology
the most significant fish source in Asia,
84 although over 160 teleost species are believed to harbor
these organisms.
45
In regard to the prevalence of anisakid larvae in fish, two extensive investigations were conducted
in the late 1970s. In one, 1010 fish belonging to 20 genera and 23 species were examined in the
Washington, DC, area and of 703 that contained parasitic nematodes, 6547 nematodes were found,
of which only 11 were Anisakis sp.
50 The mean content of nematode larvae/fish was 6.48, with an
overall infection or 69.60%. A 2-year survey in 1974–1975 of fish and shell-fish from U.S. Pacific
coastal waters off Washington, Oregon, and California included 2074 specimens.
65 Anisakis sp. was
the most frequently found, and most often on fish viscera. In fish caught off the California coast, 41.6%
contained anisakid larvae.
69 Anisakis was higher than Phocanema (Pseudoterranova), due largely to
the number of whales, a situation that is reversed in the eastern Canadian waters of the Gulf of St.
Lawrence.
65 No anisakid larvae were found in over 2000 shellfish examined. In yet another survey in
Ann Arbor, Michigan, larval densities from 63 to 91/kg of salmon tissue were found, and they were
in viable form.
87
There is some controversy as to whether there is an increased incidence of anisakid larvae in
commercial fish compared to decades ago. Clearly, these organisms are not new in fishing waters
since their presence in fish was recognized as early as 1767. One view is that the disease in humans
began to flourish when refrigeration was taken aboard fishing boats in the mid-1950s. Prior to this
time, fish were caught and eviscerated, and the infective organisms were thus discarded. When fish
are kept on ice for several days, some investigators believe the parasites migrate from the mesenteries
to muscles following the death of fish.
45,71 On the other hand, the migration of parasites in dead fish
has not been substantiated by all investigators.
Prevention
Anisakiasis can be prevented by avoiding the consumption of raw or undercooked fish. Sushi, ceviche,
and sashimi should be consumed only when properly prepared from fish that has undergone inspection
for absence of infective larvae. Infective forms can be destroyed by cooking fish to an internal temperature of 60
◦ C for 1 minute or 65
◦ C for 30 seconds.
6 Freezing at −20
◦ C or below for at least 60 hours
is reported to render the larvae uninfective.
56 Although some North American species survived after
52 hours at −20
◦ C.
6 Brining for 4 weeks has been found to render larvae uninfective.
40
REFERENCES
1. Anderson, B.C. 1985. Moist heat inactivation of Cryptosporidium sp. Am. J. Public Health 75:1433–1434.
2. Barer, M.R., and A.E. Wright. 1990. Cryptosporidium and water. Lett. Appl. Microbiol. 11:271–277.
3. Barnard, R.J., and G.J. Jackson. 1984. Giardia lamblia: The transfer of human infections by foods. In Giardia and
Giardiasis: Biology, Pathogenesis, and Epidemiology, ed. S.L. Erlandsen and E.A. Meyer, 365–378. New York: Plenum.
4. Bean, N.H., and P.M. Griffin. 1990. Foodborne disease outbreaks in the United States, 1973–1987: Pathogens, vehicles,
and trends. J. Food Protect. 53:804–817.
5. Bean, N.H., P.M. Griffin, J.S. Goulding, and C.B. Ivey. 1990. Foodborne disease outbreaks, 5-year summary, 1983–1987.
J. Food Protect. 53:711–728.
6. Bier, J.W. 1976. Experimental anisakiasis: Cultivation and temperature tolerance determinations. J. Milk Food Technol.
39:132–137.
7. Bennett, J.V., S.D. Holmberg, M.F. Rogers, and S.L. Solomon. 1987. Infectious and parasitic diseases. In The Burden of
Unnecessary Illness, ed. R.W. Amler and H.B. Dull, 102–114. New York: Oxford University Press.
8. Black, M.W., and J.C. Boothroyd. 2000. Lytic cycle of Toxoplasma gondii. Microbiol. Mol. Biol. Rev. 64:607–623.
the most significant fish source in Asia,
84 although over 160 teleost species are believed to harbor
these organisms.
45
In regard to the prevalence of anisakid larvae in fish, two extensive investigations were conducted
in the late 1970s. In one, 1010 fish belonging to 20 genera and 23 species were examined in the
Washington, DC, area and of 703 that contained parasitic nematodes, 6547 nematodes were found,
of which only 11 were Anisakis sp.
50 The mean content of nematode larvae/fish was 6.48, with an
overall infection or 69.60%. A 2-year survey in 1974–1975 of fish and shell-fish from U.S. Pacific
coastal waters off Washington, Oregon, and California included 2074 specimens.
65 Anisakis sp. was
the most frequently found, and most often on fish viscera. In fish caught off the California coast, 41.6%
contained anisakid larvae.
69 Anisakis was higher than Phocanema (Pseudoterranova), due largely to
the number of whales, a situation that is reversed in the eastern Canadian waters of the Gulf of St.
Lawrence.
65 No anisakid larvae were found in over 2000 shellfish examined. In yet another survey in
Ann Arbor, Michigan, larval densities from 63 to 91/kg of salmon tissue were found, and they were
in viable form.
87
There is some controversy as to whether there is an increased incidence of anisakid larvae in
commercial fish compared to decades ago. Clearly, these organisms are not new in fishing waters
since their presence in fish was recognized as early as 1767. One view is that the disease in humans
began to flourish when refrigeration was taken aboard fishing boats in the mid-1950s. Prior to this
time, fish were caught and eviscerated, and the infective organisms were thus discarded. When fish
are kept on ice for several days, some investigators believe the parasites migrate from the mesenteries
to muscles following the death of fish.
45,71 On the other hand, the migration of parasites in dead fish
has not been substantiated by all investigators.
Prevention
Anisakiasis can be prevented by avoiding the consumption of raw or undercooked fish. Sushi, ceviche,
and sashimi should be consumed only when properly prepared from fish that has undergone inspection
for absence of infective larvae. Infective forms can be destroyed by cooking fish to an internal temperature of 60
◦ C for 1 minute or 65
◦ C for 30 seconds.
6 Freezing at −20
◦ C or below for at least 60 hours
is reported to render the larvae uninfective.
56 Although some North American species survived after
52 hours at −20
◦ C.
6 Brining for 4 weeks has been found to render larvae uninfective.
40
REFERENCES
1. Anderson, B.C. 1985. Moist heat inactivation of Cryptosporidium sp. Am. J. Public Health 75:1433–1434.
2. Barer, M.R., and A.E. Wright. 1990. Cryptosporidium and water. Lett. Appl. Microbiol. 11:271–277.
3. Barnard, R.J., and G.J. Jackson. 1984. Giardia lamblia: The transfer of human infections by foods. In Giardia and
Giardiasis: Biology, Pathogenesis, and Epidemiology, ed. S.L. Erlandsen and E.A. Meyer, 365–378. New York: Plenum.
4. Bean, N.H., and P.M. Griffin. 1990. Foodborne disease outbreaks in the United States, 1973–1987: Pathogens, vehicles,
and trends. J. Food Protect. 53:804–817.
5. Bean, N.H., P.M. Griffin, J.S. Goulding, and C.B. Ivey. 1990. Foodborne disease outbreaks, 5-year summary, 1983–1987.
J. Food Protect. 53:711–728.
6. Bier, J.W. 1976. Experimental anisakiasis: Cultivation and temperature tolerance determinations. J. Milk Food Technol.
39:132–137.
7. Bennett, J.V., S.D. Holmberg, M.F. Rogers, and S.L. Solomon. 1987. Infectious and parasitic diseases. In The Burden of
Unnecessary Illness, ed. R.W. Amler and H.B. Dull, 102–114. New York: Oxford University Press.
8. Black, M.W., and J.C. Boothroyd. 2000. Lytic cycle of Toxoplasma gondii. Microbiol. Mol. Biol. Rev. 64:607–623.