Mold-Ripened Sausages 371(NPN) compounds (e.g., (poly)peptides,
amino - N, and ammonia - nitrogen) develop,
contributing to taste formation and to a pH -
shift in the alcalic direction (Nagy et al.
1988 ; Incze 2004a ; Talon et al. 2004 ). Cocci
play a more important role in proteolysis than
lactic acid bacteria, but molds are also active
in this process.
With similar reactions in tissue and micro-
bial enzymes, lipids are also broken down,
resulting in some fl avor development, caused
mainly by the short - chain fatty acids (Talon
et al. 2004 ). Unsaturated fatty acids are
oxidized easily; lipid oxidation is an auto-
catalytic process. Proteolytic and lipolytic
compounds do not always render a pleasant
fl avor and aroma, depending on many intrin-
sic and extrinsic factors not easy to control.
It is worth mentioning that volatile compo-
nents coming from a variety of spices, their
interaction with each other and with the meat
and fat involved, and the multilateral effect
of smoke substances do have more intensive
aroma effect than can be expected from
enzymic breakdown in sausage (Schmidt and
Berger 1998 ). It is interesting to mention that
depending on the sausage diameter, fl avor
differences can be observed: aroma is more
intense in larger sausages, due possibly to
more anaerobic fermentation. More details
on microbiological and biochemical changes
and aroma formation can be found in other
publications (Talon et al. 2004 ; Tjener and
Stahnke 2007 ) and in Chapter 9 of this book.Safety of Mold - Ripened Sausages
Dividing these products basically into two
categories depending on whether lactic
starters are used or they are manufactured by
traditional methods provides more informa-
tion on technology, microbiology, and safety
than do distinctions such as northern and
southern types (Talon et al. 2004 ). Thus,
their safety features can also be discussed
differently.information on hygienic status or spoilage
tendency, but a too high initial count may
indicate problems of a microbiological
nature.
Depending on the initial microbial load,
on the use of lactic starter, and on the tech-
nological parameters (temperature, relative
humidity, and air velocity), undesired micro-
organisms are outgrown through inhibition
by useful microorganisms, if necessary mea-
sures are taken during processing at the right
time and to the right extent. As a result of a
combination of low temperature, lowered
pH, drying (lowered a w ), and competition
with added starter cultures, if applicable, bac-
teria that are sensitive to the factors men-
tioned above change in their number and die
off. Pseudomonads cannot survive longer
than a few days; enteric bacteria do not
survive either; clostridia and staphylococci
are inhibited; and even listeriae and EHEC
strains can be inhibited in their growth. Cocci
and lactobacilli are more likely to grow, the
latter being less sensitive to low pH. As
drying proceeds, a lactobacilli - dominance
can be observed, and lactobacilli account for
the majority of microorganisms in the fi nal
product.
As a result of salt, soluble protein goes
into solution and forms a net among meat and
fat particles, which is gelifi ed by lactic acid
or by concentrating salt. This matrix ensures
good adhesion between meat and fat particles
and also good sliceability; binding and struc-
ture is formed this way (van ’ t Hooft 1999 ;
Incze 2007 ).
During ripening, tissue and bacterial
enzymic activity causes the breakdown of
protein (proteolysis) and lipids (lipolysis).
Muscle tissue enzymes (endoenzymes) play
a role in dry sausages during the fi rst part of
ripening, and enzymes of microorganisms
are responsible mainly for proteolysis and
lipolysis. As a result of this metabolism,
myofi brillar and sarcoplasmic proteins are
partly broken down and nonprotein nitrogen