Taste and Odor Problems in Fish from
Michigan Waters
CARLOS M. FETTEROLF, JR., Aquatic Biologist
Michigan Water Resources Commission
Lansing, Michigan
The pubUc act which created the Michigan Water Resources Commission in
1949 states in part that it shall be unlawful for any person to discharge into the
waters of the state any substance which is injurious to the conducting of a lawful
occupation or which destroys or impairs the value of lawfuUy taken fish or game.
The lowering of palatibility and acceptabflity of fish constitutes an impairment of
value. An injury to a lawful occupation occurs if commercially harvested fish are
not salable because of off-flavor. However, tracing a lowering of palatability to
a source and attempting to show responsibility is often difficult.
This paper outlines the general problem, summarizes Michigan's recent complaints of fish off-flavor, discusses the mechanics of uptake of tainting substances
by fish, and relates the results of two recent investigations. Throughout this discussion, odor and aroma refer to the olfactory sensation derived upon sniffing
through the nose. Taste and flavor refer to the olfactory sensations noted when
food is in the mouth or shortly after it is swaUowed or removed. Taint denotes the
presence of a contaminant noticeable by taste or odor.
Problems of malflavors in water supplies have received considerable attention
in the literature. It is general knowledge that algae, the actinomycetes, decaying
vegetation, and discharges of domestic and industrial wastes can be responsible for
taste and odor. The currently accepted technique for evaluation of malflavors is
the threshold odor procedure described in Standard Methods(l). This test measures
the minimum concentration at which a substance can be detected by odor alone.
Until recently, the problem of malflavors being taken up by fish has received
scant attention. Although sensory testing of foods is commonplace in industry,
academic institutions, and research laboratories the technique has rarely been
applied to assay the effects of tainted water on fish flavor. Organoleptic tests of
fish are usuaUy employed to determine the effects of different methods of handling, processing, storing, and packaging.
In the last eight years limited information on tainting by uptake of contaminants from natural and controUed environments has become available. The
Aquatic Life Advisory Committee ofthe Ohio River Valley Water Sanitation Commission (2) lists the work of Bandt (3) and uncredited sources on concentrations of
several phenolic substances which affect taste and odor of fresh-water fishes. They
cite 0.1 mg/l of coal-coking wastes, coal-tar wastes, phenols in a polluted river,
and a pure compound of chlorophenol as having been responsible for taste and odor
in fish flesh. Other materials causing similar problems at concentrations of 1 mg/l
or less were listed as xylenols, p-qumone, napthalene, d-napthol, and quinoline.
A. W. Winston, Jr. (4), in a mimeographed release of the Dow Chemical
Company, reported on a method of establishing the concentration of a compound
in the water which would impart a threshold taste to fish. Fish were held in
known constant concentrations for seven days before part were cooked and taste-
tested by a trained panel in a procedure patterned after the water odor threshold
test (1). If no taste was established, the remaining fish were held an additional
seven days before retesting.    Winston's results (Table I) reveal the abifity of fish
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