Nitrate and nitrite levels in pike-perch fillet (Sander lucioperca)
marketed in Germany
Received: 11 September 2017 / Accepted: 3 January 2018 / Published online: 23 January 2018
Ó Bundesamt fu¨r Verbraucherschutz und Lebensmittelsicherheit (BVL) 2018
The study was undertaken to present preliminary results of the nitrate and nitrite content in the muscle ﬂesh of pike-perch
marketed in Germany. Frozen ﬁllet products of different origin, fresh ﬁsh from an inland freshwater lake and from
intensive warm water aquaculture in a recirculation aquaculture system (RAS) were analyzed. Despite relatively elevated
levels of 31.9 mg nitrate/kg in pike-perch from RAS, amounts were generally low.
Keywords Wild pike-perch Á Farmed pike-perch Á Frozen food Á Muscle ﬂesh Á Intensive aquaculture Á RAS
In our ecosystem, nitrite and nitrate are natural components
of the nitrogen cycle. Their occurrence in the environment
and particularly in the food chain is a matter of concern.
Although nitrate/nitrite related beneﬁcial or adverse health
effects are being discussed for years, they are not com-
pletely clariﬁed yet (Hord et al. 2009; Lundberg et al.
2009). Both are not carcinogenic per se, but under condi-
tions that result in endogenous nitrosation, it cannot be
excluded that ingested nitrate and nitrite may be a risk
factor for cancer (Habermeyer et al. 2015). However, there
are ongoing attempts to limit or reduce these substances in
food. To protect the consumer against health risks, limits
have been set for the nitrate content; the lowest value of
200 mg nitrate/kg is applicable to cereal-based foods and
baby food (EU 2011).
Nitrite can react with secondary amines to produce
N-nitroso compounds, most of which have proven to be
carcinogenic in animal tests (WHO 2003). The European
Food Safety Authority (EFSA) has established accept-
able daily intakes (ADI) for nitrite and nitrate. The current
acceptable ADIs are 0.07 mg/kg bw (body weight)/day and
3.7 mg/kg bw/day, respectively (EFSA 2017). For live ﬁsh,
mainly water soluble nitrite is a well-known toxicant, but
the level for intoxication varies considerably and depends
on a large number of external and internal factors (Krou-
pova et al. 2005).
Apart from raising ﬁsh in open ponds and raceways,
recirculation aquaculture systems (RAS) represent a new
way to farm ﬁsh. These in house facilities operate by
cleaning the water from the ﬁsh tanks, so it can be reused.
It reduces the water demand dramatically, but potentially
raises the levels of nitrogenous compounds. Effective bio-
ﬁltration systems must purify the wastewater for the
recycling. Particularly ammonium excreted through the
ﬁsh gills rose in RAS, and subsequently have to be
removed by bio ﬁlters through the process of nitriﬁcation.
In two steps, ammonium (NH
) is initially oxidized to
), which then gets converted to nitrate
) by bacteria.
Fish is normally not considered as a source of nitrates
and nitrites. The number of recent investigations for ﬁsh
and ﬁsh products is rather limited. The most detailed study
with 21 different marine ﬁsh species, some crustaceans and
mollusc species was carried out 20 years ago (Karl 1998).
The majority contained low levels of \ 2mg NO
although a higher value of 100 mg NO
/kg was analyzed
Journal of Consumer Protection and Food Safety
r Verbraucherschutz und Lebensmittelsicherheit
& Monika Manthey-Karl
Department of Safety and Quality of Milk and Fish Products,
Max Rubner-Institut, Federal Research Institute of Nutrition
and Food, Hermann-Weigmann-Straße 1, 24103 Kiel,
State Research Center for Agriculture Mecklenburg-
Vorpommern, Institute of Fisheries, Malchower Chaussee 1,
17194 Hohen Wangelin, Germany
Journal of Consumer Protection and Food Safety (2018) 13:131–134