Starter Cultures for Meat Fermentation 211relation between pH and BA contents, the
lowest pH generally being characterized by
highest amine levels (Vandekerckove 1977 ;
Eitenmiller et al. 1978 ; Hal à sz et al. 1994 ;
Bover - Cid et al. 1999 ; Parente et al. 2001 ),
according to the hypothesis that biogenic
amine production could be a protective
mechanism for microorganisms against
acidic environmental conditions.
The fi nal BA contents in fermented sau-
sages depend on the microbial composition
of meat used as raw material, but also on the
type and activity of the starter culture inocu-
lated. Most strains of L. curvatus , one of the
main species used as a starter in sausage pro-
duction, are associated with high BA produc-
tion (Bover - Cid and Holzapfel 1999 ; Pereira
et al. 2001 ).
The use of starter cultures with negative
decarboxylase activity was shown to prevent
the growth of biogenic amine producers and
lead to end products nearly free of BA, as
long as the raw material was of suffi cient
quality. Several papers have reported on the
ability of selected starter culture ( L. sakei
CTC494) to greatly reduce BA accumulation
in fermented sausages (Bover - Cid et al.
2001 ; Gonz á lez - Fern á ndez et al. 2003 ). This
negative - decarboxylate strain can decrease
the pH quickly during the fermentation step
and be predominant throughout the process,
thus preventing the growth of bacteria that
can produce BA.
The introduction of starter strains that
possess amine oxidase activity might be
a way to further decrease the amount of
BA produced during meat fermentation
(Martuscelli et al. 2000 ; Fadda et al. 2001b ;
Gardini et al. 2003 ; Suzzi and Gardini
2003 ).Antibiotic Resistance
The safety of bacterial strains intentionally
added to food, such as starter cultures used
for meat products, is becoming an issue.
Although meat starter cultures have a longresistance to antibiotic are major concerns
in CNS.
Biogenic Amines
The accumulation of biogenic amines (BA)
in foods requires the presence of amino acid
precursors, microorganisms with amino
acid decarboxylase activity, and favorable
conditions (temperature and pH) for growth
and decarboxylation. The large quantities of
protein present and the proteolytic activity
found during the ripening of meat products
provide the precursors for later decarboxyl-
ase reactions performed by both starter cul-
tures and wild microbiota (Suzzi and Gardini
2003 ; Komprda et al. 2004 ). The presence in
food of biogenic amines (BA), such as cadav-
erine, putrescine, spermidine, histamine,
phenethylamine, agmatine, and tyramine, is
a health concern because their biological
effect can lead to toxicological symptoms,
such as pseudo - allergic reactions, histaminic
intoxication, and interaction with drugs
(Shalaby 1996 ). Excessive consumption of
these amines could cause nervous, gastric,
intestinal, and blood pressure problems
(Suzzi and Gardini 2003 ). Nowadays,
increasing attention is given to BA because
of the growing number of consumers who are
sensitive to them; in such people, the action
of amine oxidases, the enzymes involved in
the detoxifi cation of these substances, is defi -
cient (Suzzi and Gardini 2003 ). High levels
of BA, especially tyramine but also hista-
mine and the diamines putrescine and cadav-
erine, have been described in fermented
sausages (Hern á ndez - Jover et al. 1997a, b ;
Bover - Cid et al. 2000a, b ).
Many LAB from meat and meat products
can decarboxylate amino acids (Bover - Cid
and Holzapfel 1999 ). Rosenstein et al. ( 2009 )
reported that S. carnosus encodes an orni-
thine decarboxylase (Sca0122) that could
account for the synthesis of putrescine
from ornithine or cadaverine from lysine.
Many studies have reported a signifi cant cor-