PREVENT HISTAMINE POISONING IN YOUR FISH!
by Jerald Horst
(Revised September 2003)
Histamine
poisoning is among the top three seafood illnesses reported
in the United States. Many instances of it, especially in
recreational-caught fish, go unreported to health officials.
Large amounts of histamine can be formed in these fish if
they are poorly handled and temperature-abused.
The symptoms
of histamine poisoning can include dizziness, headache, facial
swelling and flushing, nausea, abdominal cramping and diarrhea,
difficulty in swallowing. Although most victims recover within
24 hours especially with the help of antihistamines, some
suffer for a longer period because individuals have different
levels of sensitivities to histamine. Prevention is possible
with proper handling.
Histamine
is a chemical found in many scombroid fish – popular
sport species with spiny fins. These species include such
favorite offshore targets such as tunas, mahi mahi, marlin,
amberjack and wahoo, as well as other sportfish such as bluefish
and mackerels.
These
fish naturally contain relatively large amounts of histidine
(an amino acid) in their muscle. After the fish dies, the
variety of live bacteria on the fish continue to grow, and
in the process, can change histidine to histamine,
especially at high, Gulf water temperatures.
The bacteria
responsible for forming histamine may occur naturally in the
living fish or may be added during handling. If the captured
fish is left unattended, the water and air temperatures of
the Gulf region provide excellent opportunities for the rapid
growth of histamine-forming bacteria, increasing the risk
of histamine poisoning. A popular sport-fishing species, tuna,
has body temperatures above that of the surrounding water,
and these temperatures are further elevated while fighting
during capture. When a tuna is brought on board, its body
temperature can be 10 or more degrees higher than the water
temperature. This further increases the potential of histamine
formation.
How can sport fishermen reduce the possibility of histamine
poisoning from their catches? Chill the fish as rapidly as
possible!
Rapidly
chilling catch to prevent histamine formation has additional
benefits, regardless of species. Spoilage and quality loss
due to other bacteria and natural processes are also strongly
affected by temperature. Rapid chilling maintains and lengthens
the initial good quality of the meat and delays spoilage.
Even if plans are to freeze the fish at the end of the day
for future consumption, rapid chilling on board will prevent
the formation of histamine and retain good quality levels
until it is properly packaged and frozen.
Simple
Techniques to Chill Fish and Prevent the Formation of Histamine
- Before
leaving the dock, pack cooler(s); large enough for the fish
you hope to catch, full with bags of ice.
- On
the water, before casting, prepare the coolers by opening
a couple bags of ice and forming a layer of ice on each
cooler bottom. Return the other ice bags, unopened to the
cooler for storage.
- As
soon as the fish is brought on board, stun it by clubbing
it with a blunt instrument, aiming for the soft part of
the head between the eyes.
- Place
the fish in the ice chest on the layer of ice. Open additional
bags of ice and cover and completely surround the fish,
using two pounds of ice for each pound of fish.
Two pounds
of ice for every pound of fish is recommended to rapidly chill
the fish. For commercially caught tuna, the US Food and Drug
Administration (FDA) recommends that large, whole tuna be
chilled to a 50°F internal temperature within 6 hours
of capture, and then further chilled down to 40° F within
24 hours.
- Bleeding
and gutting the fish can assist rapid chilling. Gutting
will also remove a source of bacteria, if done carefully.
The bacteria must be contained. When gutting, do
NOT cut through the belly wall into the meat.
After gutting, pack ice firmly into the belly
cavity before covering the fish with ice.
References
Kaneko,
J.J. 2000. Development of a HACCP-based strategy for the control
of histamine for the fresh tuna industry. Final report NOAA
Award # NA86FD0067, PacMar, Inc., Honolulu, Hawaii.
Price,
R.J. 1989. Why seafood spoils. California Sea Grant Extension
Program, Publication UCSGEP-89-3, University of California,
Davis.
