Starter Cultures for Meat Fermentation 209LAB, referred to as bioprotective cultures.
Bioprotective cultures may act as starter cul-
tures in food fermentation processes, such as
dry sausage manufacturing, or they may
protect foods without any detrimental organ-
oleptic changes.
The ability to produce different antimicro-
bial compounds, such as bacteriocins and/or
low - molecular mass antimicrobial com-
pounds, may be one of the critical character-
istics for effective competitive exclusion. As
mentioned above, one of the main roles of
meat LAB starter cultures is the rapid pro-
duction of organics acids; this inhibits the
growth of unwanted biota and enhances
product safety and shelf life. Likewise,
several authors have reported the role of
Staphylococcus in proteolysis, lipolysis, and
formation of fl avor in sausages (Berdagu é et
al. 1993 ; Montel et al. 1998, 1996 ; Engelvin
et al. 2000 ; Stahnke 2002 ; Olesen et al. 2004 ;
Tjener et al. 2004 ). Some strains are able to
produce antimicrobial substances (Mart í n
et al. 2007 ).
The production of bacteriocins, one of the
most promising technological features of
starter cultures, is discussed in Chapter 14.Probiotics
Foods that have health benefi ts beyond their
nutritional content (functional foods), and
particularly foods containing probiotics, are
products that are growing in popularity.
Probiotics are available as dietary supple-
ments or they may be incorporated directly
into foods. They are live microorganisms that
when administered in adequate amounts,
confer a health benefi t to the host (FAO
2006 ); they are added to a variety of foods.
Recently, attention has been directed to the
use of fermented sausages as a food carrier
because these products could contain high
numbers of viable lactic acid bacteria. To use
probiotics as starter cultures for fermented
sausages, in addition to the demonstrated
probiotic features (FAO 2006 ), other proper-
ties are demanded.curing conditions to the generation of hydro-
philic peptides and free amino acids by the
proteolytic activity of L. curvatus CRL 705.
Moreover, it has been demonstrated that L.
sakei plays an important role in amino acid
generation (Fadda et al. 1999a, b ; Sanz et al.
1999 ).
Lipolysis, together with proteolysis, is
believed to play a central role in aroma
formation. This phenomena is only the fi rst
step in the process and is followed by further
oxidative degradation of fatty acids into
alkanes, alkenes, alcohols, aldehydes, and
ketones (Viallon et al. 1996 ; Chizzolini et al.
1998 ), which enhances the development of
the fl avor. In fact, medium - and long - chain
fatty acids act as precursors of aroma com-
pounds, whereas the short - chain fatty acids
(Co6) lead to strong cheesy odors (Ansorena
et al. 2001 ). Although some authors
(Molly et al. 1997 ; Kenneally et al. 1998 ;
Galgano et al. 2003 ) have concluded that
tissue lipases are primarily responsible for
lipolysis during fermentation, numerous
studies over the last decade described
lipolytic bacteria, especially staphylococci
(Hugas and Monfort 1997 ; Montel et al.
1998 ; Mauriello et al. 2004 ). Hugas and
Monfort (1997) highlighted the need to use
selected strains of Gram - positive, catalase -
positive cocci to ensure sensory quality of
fermented sausages. Moreover, Stahnke et al.
(2002) , Beck et al. (2004) , and Olesen et al.
(2004) described the capability of
Staphylococcus xylosus and Staphylococcus
carnosus strains to modulate the aroma
through the conversion of amino acids and
free fatty acids (FFA). Strains of S. xylosus
have been recommended for the production
of the very aromatic sausages of southern
Europe (Samelis et al. 1998 ).
Bacteriocin and Biopreservation
In recent years, there has been a considerable
increase in studies of the natural antimicro-
bial compounds on and in food produced by