Detection of Chemical Hazards 471are analyzed with liquid chromatography
atmospheric pressure chemical ionization
mass spectrometry and tandem mass spec-
trometry (Eerola et al. 1998 ; Rath and Reyes
2009 ).Biogenic Amines
Biogenic amines are produced through
microbial decarboxylase activity against pre-
cursor amino acids. Consequently, tyramine
is produced from tyrosine, tryptamine from
tyrptophan, histamine from histidine, phenyl-
ethylamine from phenylalanine, cadaverine
from lysine, agmatine from arginine, and
putrescine from ornithine. Polyamines
spermine and sperdimine follow a different
generation route, usually originated from
putrescine. Low amounts of amines con-
sumed in meats are generally degraded in
humans by the enzyme monoamine oxidase
(MAO) through oxidative deamination reac-
tions. However, when signifi cant amounts
are consumed, some risk situations like
hypertensive crisis may appear due to their
vasoactive and psychoactive properties.
The presence of these amines in meat may
be an indication of its hygienic quality. Thus,
the presence of cadaverine and/or putrescine
may indicate the presence of contaminating
meat fl ora. In other cases, the processing con-
ditions are very important for the generation
of biogenic amines, especially in fermented
meats where the decarboxylase activity in
any of the microorganisms of natural fl ora or
microbial starters must be carefully con-
trolled. For instance, certain lactic acid bac-
teria with decarboxylase activity can generate
tyramine from tyrosine (Eerola et al. 1996 ).
The estimated tolerance level for this amine
is 100 – 800 mg/kg (Nout 1994 ), but larger
ingested amounts may result in higher blood
pressure and the risk of hypertensive crisis
(Shalaby 1996 ). Other amines like phenyle-
thylamine may cause migraine and increases
in blood pressure.can also contribute. In general, nitrite rapidly
decreases during processing and thus remains
at low residual content in the fi nal product
(Hill et al. 1973 ). It was recommended to
reduce the levels of nitrites and add ascorbate
or erythorbate to favor the reduction of nitrite
to nitric oxide and thus, the inhibition of
nitrosamines formation (Cassens 1997 ).
Ascorbate is better than ascorbic acid because
it reacts with nitrite 240 times faster (Pegg
and Shahidi 2000 ). As an example, the resid-
ual nitrite content in fermented sausages
was found to be below 20 mg/kg in most of
the products surveyed in the late 1990s
and early 2000s in Europe (EFSA 2003 ).
Nitrosodimethylamine and nitrosopiperidine
were reported as the main nitrosamines
found at levels above 1 μ g/kg. The levels of
nitrosamines were found to be rather poor
or even negligible in European fermented
sausages assayed in the framework of a
European project (Demeyer et al. 2000 ).
Some N - nitrosamines appear to be generated
in packaged dry - cured ham because of the
reaction of nitrite with amine additives
present in the rubber nettings (Sen et al.
1987 ). Regulations on nitrate and nitrite have
been recently modifi ed in the European
Union according to the Directive 2006/52/EC
of 5 July 2006 that modifi es previous
Directive 95/2/EC on additives other than
colors and sweeteners.
Different types of extraction can be used
for the separation of nitrosamines from the
meat matrix. These techniques include
steam distillation, liquid - liquid extraction,
solvent extraction, solid phase extraction,
and supercritical fl uid extraction (Fiddler and
Pensabene 1996 ; Raoul et al. 1997 ; Rath and
Reyes 2009 ). Once extracted, volatile
N - nitrosamines, or nonvolatile nitrosamines
previously derivatized by acylation or tri-
methylsilylation, are usually analyzed by gas
chromatography coupled to a thermal energy
analyzer or mass spectrometry detectors in
case a specifi c identifi cation and confi rma-
tion is necessary. Nonvolatile nitrosamines