380 Chapter 22
stuffed in medium - and large - diameter
natural casings; the length of fermentation
and drying/smoking depends on their type
but rarely exceeds several days. The fi nal pH
of semidry sausages is explicitly acid (4.7 to
5.2 – 5.4), with a lactic acid content of 0.5%
to 1.3%; although they are often fi nely
chopped and spreadable, many of them can
be sliced, their moisture being 35% or higher.
Semidry sausages are often smoked and
slightly cooked by the heat used in the
smokehouse, which occasionally reaches
nearly 60 ° C for a strictly limited time. After
smoking, the sausages may be air dried for a
relatively short time. Compared with dry sau-
sages, these products show higher a w values
( > 0.90 – 0.91), so that a lower pH is needed
for satisfactory protection against undesired
microorganisms. However, due to their M : P
ratio ranging from 2.3 : 1 to 3.7 : 1, semidry
sausages require refrigeration. This category
of sausages is popular in Northern European
countries and in North America. The use of
starter cultures to produce semidry fermented
sausages has proved to be particularly suc-
cessful to keep their stability.Dry Fermented Sausages
In general, these products have a fi nal pH
ranging between 5.2 and 5.8, which is con-
sistent with the lower lactic acid content
(0.5% – 1.0%), a moisture lower than 30%,
and an M : P lower than 2.3 : 1. The main dif-
ference with semidry fermented sausages is
the long ripening and drying process, during
which biochemical and physical changes
occur that strongly infl uence their stability
and safety. Due to a w , which ranges from
0.85 to 0.91, dry fermented sausages exhibit
high shelf stability and can be kept without
refrigeration. The typical lower a w values of
these products is achieved by air - drying in
Mediterranean countries and by smoking in
northern countries. The long ripening process
of dry fermented sausages promotes the
growth of starter cultures, which contributesture : protein ratio (M : P), weight loss, a w ,
surface treatment, meat and fat comminution
degree, and geographical region. Semidry
and dry fermented sausages can be distin-
guished on the basis of a w value (Incze 2004 )
or M : P ratio (Sebranek 2004 ). These param-
eters are mainly applied in Europe or in the
United States, respectively. In terms of shelf
life and safety, moisture content alone is not
suffi ciently informative compared with a w
and pH values. The combination of initial
moisture/salt and moisture/protein contents,
as well as the extent of drying, will determine
fi nal a w and M : P ratio, respectively. More
specifi cally, M : P ratio provides information
about the extent of drying of the lean meat
portion. Nevertheless, fi nal values of 0.90 to
0.91 for a w and 2.0 : 1 for M : P ratio can be
considered as the borderline defi ning dry and
semidry fermented sausages. Even when sau-
sages with similar names are very different
according to the region in which they are
produced, a general classifi cation based on
fi nal moisture content, a w level, and M : P
ratio was attempted by Ockerman and Basu
(2007). In this chapter, a description based
on two groups of fermented sausages,
semidry or quickly fermented and dry or
slowly fermented sausages, is reported.
Semidry Fermented Sausages
These sausages differ greatly from dry sau-
sages because of their pronounced tangy
fl avor from forced fermentation, resulting in
lactic acid accumulation and a bulk of other
products from fermentation breakdown. The
term “ semidry ” is unequivocal; these prod-
ucts are dryer than water - added cooked meat
products but have a higher moisture content
than dry sausages (Incze 2007 ). In the United
States, semidry sausages are fermented and
cooked but are not usually dried (Sebranek
2004 ), while in Europe they involve a broader
range of products, most of them experiencing
weight loss after fermentation because of
cooking or hot smoking. They are usually