U. S. Food and Drug Administration
Center for Food Safety and Applied Nutrition
FDA Prime Connection

Institute of Medicine - A Guide for Marine Recreational Fishing
 
 
                         Recreational Seafood Safety
 
                    A Guide for Marine Recreational Fishing
 
                             Institute of Medicine
                         National Academy of Sciences
 
                           Report of Seafood Safety
 
                        Sea Grant Extension Bulletin-18
 
 
  >"Most seafoods available to the U.S. public are wholesome and unlikely to
  > cause illness in the consumer."
 
 
Contents
 
    <*> Introduction
 
        <*> Seafood Health Risks in Perspective
 
    <*> Consumption of Raw Seafoods
 
        <*> Eating Raw Fish or Shellfish
 
    <*> Seafood from Specific Locations
 
        <*> Ciguatera
        <*> Tetrodotoxin
        <*> Red Tide
 
    <*> Mishandling
 
        <*> Scombroid Poisoning
        <*> Cross-Contamination of Ready-To-Eat Seafood
 
    <*> Chemical Pollutants
 
        <*> Recreational Health Risks
 
    <*> Maintaining Quality in the Catch
 
        <*> Handling
        <*> Cleaning
        <*> Icing
 
    <*> Contacts for Additional Information
 
 
Recreational fishing produces a significant portion of all the edible fish and
shellfish harvested annually in Florida. Current estimates by the National
Academy of Sciences suggest the nationwide recreational catch contributes more
than 20 percent of the annual amount of seafoods consumed in the United States.
These estimates emphasize the importance of protecting both the quality of the
catch and the quality of our inland and coastal waters.
 
Sport-caught seafoods from marine waters offer many noted nutritional attributes.
The basic benefits of high quality, easily digested protein and low fat content
are accompanied by a full complement of minerals, vitamins and the unique,
healthful omega-3 fatty acids. Recent studies have linked seafood consumption
with a variety of health benefits including decreased risk from cardiovascular
disease. These benefits further enhance the enjoyment of recreational fishing.
 
 
SEAFOOD HEALTH RISKS IN PERSPECTIVE
 
Illnesses associated with seafood consumption can be grouped into four general
categories:
 
    <*>
    <*> consumption of raw seafoods,
    <*> eating certain types of seafood from certain locations,
    <*> mishandling, and
    <*> chemical pollutants.
 
Avoidance and prevention of these problems require common sense and awareness of
the potential causes.
 
 
CONSUMPTION OF RAW SEAFOODS
 
Raw Seafood Concerns:
 
Eating raw fish or shellfish is the most frequent cause of seafood-borne
illnesses. These raw foods carry bacteria and other contaminants that may be
harmful to consumers. This eating preference is of particular concern for
consumers with health conditions that impair their health defense systems.
 
Live oysters and clams filter enormous amounts of water to obtain food. This same
water may contain potentially harmful types and amounts of bacteria and virus
that can concentrate and survive in the shellfish. Mishandling of the
recreational harvest can further contribute to the growth and survival of
bacteria.
 
Similarly, some live fish can carry parasites which are part of the natural
ecology of the marine environment. In most instances these marine parasites are
not harmful to humans and are simply destroyed by human digestion. Although the
occurrence of a marine parasite infection in humans from eating raw fish is very
rare, the unpleasant thought of eating a parasite is enough reason for caution.
 
 
CONSUMPTION OF RAW SEAFOODS
 
Raw Seafood Safety:
 
Consumers with comprised health conditions that impair their health defense
systems should not eat raw shellfish! Despite regulatory monitoring and approval
of waters, certain bacteria which can infect compromised consumers may be present
on raw oysters or clams. One example is Vibrio vulnificus which has caused death
in consumers who are in the so-called 'health risk categories.'  These bacteria
are easily destroyed by thorough cooking.
 
Some raw marine fish can contain parasites often called 'worms' or 'cysts.'
Those visible about the gut or surface of the fish muscle can be easily removed
with a knife. Ones that are not removed are easily destroyed by customary
cooking.
 
An added safety measure for consumers desiring raw fish or sushi is to place the
seafood in frozen storage (ideally below 0 degrees F for at least 48 hours prior
to serving). This technique kills the parasites. Much of the desired raw fish
quality can be retained by rapid freezing methods such as packing fillets in a
thin, 1-inch layer and then laying them in frozen storage with ample cold air
exposure. Frozen fillets should be slowly thawed in refrigeration (32-38 degrees
F).
 
Health conditions which impair health defense systems include:
 
    <*> liver disease, including cirrhosis and hemochromatosis,
    <*> chronic alcohol use,
    <*> cancer (especially if taking anti-cancer drugs or radiation treatment),
    <*> lymphoma, leukemia, AIDS, Hodgkin's disease,
    <*> diabetes mellitus,
    <*> chronic kidney disease,
    <*> inflammatory bowel disease,
    <*> any person receiving immunosuppressive drugs,
    <*> steroid dependency (as used for conditions such as chronic obstructive
        pulmonary disease),
    <*> achlorhydria (a condition in which the normal acidity of the stomach is
        reduced or absent), and
    <*> medicines that reduce stomach acid.
 
 
SEAFOOD FROM SPECIFIC LOCATIONS
 
Ciguatera Concern:
 
Ciguatera is most common in certain true tropical reef areas as in the Caribbean
region. Ciguatoxic fish cannot be detected by appearance, taste or smell.  Raw
and cooked whole fish, fillets or parts have no signs of spoilage,discoloration
or deterioration. The toxins present cannot be completely destroyed or removed
by cooking or freezing.
 
Ciguatera Prevention:
 
Unfortunately, the documentation, verification and utility of a reliable
ciguatoxic fish list is seriously compromised by the diversity of fish species
and variable nomenclature. For example, local fishermen may refer to a variety
of fish as "jacks" or "snappers" when they are actually a mackerel, wrasse or
other species. Certain species of snapper and grouper are never implicated in
ciguatera, yet their popular reputation suffers from species misidentification.
 
Selecting smaller fish, which are likely to accumulate less toxin, offers limited
guidance due to variable sizes per species. Particularly large fish of any
tropical species from Caribbean reef zones should be avoided. Likewise, barracuda
is a reef fish eater that is not recommended for consumption.
 
Learning about potential ciguatoxic areas and fish remains the best method for
avoiding this unusual form of food poisoning. Consumers purchasing tropical
marine fish known to occur about reef waters should patronize reputable dealers
and restaurants. Vacationers and experienced recreational fishermen should
exercise caution in areas of concern for particular tropical fish.
 
 
SEAFOOD FROM SPECIFIC LOCATIONS
 
Pufferfish Poisoning (PFP):
 
Tetrodotoxin can be used in reference to a rare, but potentially severe illness
that can result from consumption of a small group of fish -- the pufferfish or
so-called blowfish or balloonfish. Certain species of pufferfish have been known
to produce this toxin which can be stored in the viscera or edible muscle of the
fish. If consumed, this toxin can cause a potentially lethal condition known as
"fugu poisoning" in some oriental countries.
 
PFP Prevention:
 
The edible muscle from pufferfish is tasty and many species are eaten, yet most
consumers are not able to distinguish the potentially dangerous vs. safe species.
For example, in Florida there are six to eight species of pufferfish and studies
have shown some of these species can produce toxins. Experience and training are
necessary to properly distinguish the species. For these reasons, the safest
recommendation is do not eat pufferfish caught in Florida.
 
Red Tide Concern:
 
Florida's Red tides are produced by massive growths of certain types of
microplankton that kill fish and contaminate filter-feeding molluscan shellfish
like clams. The toxins produced by these plankton are persistent in raw, frozen
and cooked forms. Likewise, the toxins can be air-borne in rough coastal surf and
if inhaled can cause respiratory and eye irritation.
 
Red Tide Safety:
 
Do not harvest shellfish or dying fish from known regions of red tide.
Occurrence is typically seasonal (spring and early summer) along Florida's
southwest coast, yet cases have been recorded out of season and in nearshore
regions of the east and Gulf coasts of Florida. Consult regional offices of
public health and the Florida Department of Natural Resources for advisories.
Toxic regions will recover after the plankton and toxins dissipate.
 
 
MISHANDLING THE CATCH
 
Scombroid Poisoning Problem:
 
Scombroid Poisoning Prevention:
 
Ready-To-Eat Seafood Concern:
 
Ready-To-Eat Seafood Safety:
 
 
CHEMICAL POLLUTANTS
 
Chemical Contamination Concern:
 
Recreational health risks from pollutants such as heavy metals (mercury), various
pesticides, and other chemicals are difficult to assess because any possible
related illnesses are not obvious and are not limited to one particular exposure
or cause. Prior publicity and public reaction has heightened concern, but there
are no data to warrant alarm. Responsible federal and state health and
environmental agencies will issue specific warnings for locations or species if
their continuing tests determine concerns. Presently, concern is primarily
focused on aquatic species from inland, freshwater sources. Chemical
Contamination Safety: Public health advisories are sometimes issued as guidelines
for the consumption of seafood.  These advisories are based on water and seafood
analyses, and health risk judgments. There is growing concern for the quality of
some of Florida's freshwaters because of continuing development and pollution.
 
Fishermen should be mindful of future advisories, carefully distinguishing
official releases from publicity and local reports. The state authority for
public health advisories is the Florida Department of Health and Rehabilitative
Services. These advisories can be accessed through local, city and county health
departments.
 
Official advisories attempt to account for variations in contaminants, predicted
consumption patterns and probable long-term consequences. Fishermen should not
generalize about advisories on one fish, contaminant or area.  Contaminated fish
from one area do not imply that the same fish from other areas or other fish in
the same area are also contaminated. Environmental contamination, in terms of
seafood safety, is usually a site specific problem.
 
MAINTAINING QUALITY IN THE CATCH
 
Handling:
 
If fish remain exposed to the sun and the air on deck or shore, summertime
temperatures and solar insulation can cause quality problems in less than one
hour. However, simply chilling seafood can prevent quality deterioration and
reduce the health risks which can result from elevated temperatures. Proper icing
can be accomplished with a little advance planning and some relatively
inexpensive equipment.
 
Cleaning:
 
Icing:
 
Both crushed or flaked freshwater ice are good for rapid chilling of cleaned
fish. Fish stored in crushed or flakes of ice remain moist and glossy and do not
dry out as fast as fish placed in refrigerated storage without ice.
 
Each vessel operator should decide how much ice is needed for each fishing trip
by taking into account the length of the trip, water and air temperatures, and
as nearly as possible, the size of catch expected. It's better to throw out ice
than fish at the end of a trip.
 
In general, fish stored in coolers will be well-chilled when:
 
 
 
     1.   three (3) inches of ice covers the bottom of the box;
     2.   fish are laid in the cooler and mixed with ice, and contents are
          covered with another layer of ice three inches deep.
     3.   the cooler contains one pound of ice for each pound of fish stored in
          it.
 
After unloading, throw out all remaining ice to prevent bacterial buildup between
trips. To kill bacteria and prevent contamination of new ice, thoroughly wash and
rinse the inside of the cooler, then do a final rinse with chlorinated water or
bleach and water solution.
 
 
FOR ADDITIONAL INFORMATION:
 
Regulatory Authorities
 
For general advice and specific information on harvestable shellfish waters and
red tides write:
 
Florida Department of Natural Resources
Shellfish Environmental Assessment Section
Mail Station 205
3900 Commonwealth Blvd.
Tallahassee, FL 32399
 
For information on obtaining public health advisories from state agencies and
local/county health programs, write:
 
State Health Office
Florida Dept. of Health & Rehabilitative Services
1317 Winewood Blvd.
Tallahassee, FL 32399-0200
 
Educational Information:
 
For general advice and related publications, contact your local county
extension office or write:
 
Florida Sea Grant College Program
Building 803, Rm. 4
University of Florida
Gainesville, FL 32611-0341
 
Recreational Seafood Safety was written by: Dr. Steven Otwell
Sea Grant Seafood Specialist
Food Science and Human Nutrition Dept.
University of Florida
Gainesville, Florida
 
&
 
Frank Lawlor
Sea Grant Extension Agent
Palm Beach County Extension Office
Palm Beach Gardens, Florida
 
                                                                    (06/09/95)