Dry-Cured Ham 359decarboxylase activity. Some molds (usually
Penicillium ) and yeasts (mainly Candida
zeylanoides and Debaryomices hansenii )
may grow and develop on the outer surface
of the ham if it is stored in high humidity and
high temperatures (Toldr á 2004, 2006b ).Recent and Future Trends
Dry - curing of hams is a very long and slow
process, and for this reason there have been
many proposals to accelerate it (Marriott
et al. 1987, 1992 ). Initial strategies were
based on boning and skinning of hams for
better penetration and diffusion of salt into
them (Montgomery et al. 1976 ; Kemp et al.
1980 ; Marriott et al. 1983 ); in other cases,
better diffusion was achieved by tumbling of
hams in rotating drums, even though some
physical damage did occur (Leak et al. 1984 ).
Freezing and thawing of hams produces a
membrane disruption that can also facilitate
salt diffusion (Kemp et al. 1982 ), and an
accelerated protein and lipid hydrolysis
during the initial months has been reported,
even though differences tend to minimize
with time (Motilva et al. 1994 ).
Other recent proposals have been based
on the simultaneous vacuum brine impregna-
tion method that can be applied with fresh
hams or while frozen hams are thawed
(Flores et al. 2009 ). This process gives a sub-
stantial reduction in the time needed for
thawing and salting, without affecting the
biochemical reactions taking place during the
processing (Barat et al. 2006 ) or the sensory
quality of the fi nal product (Flores et al.
2006 ). The control of proteolysis in dry -
cured ham is an important development that
has been recently proposed (Toldr á 2006b ).
This uses the process parameters (pH, salt
content, water activity, etc.) to control the
muscle endoproteases, mainly involved
in texture degradation, and exoproteases,
directly involved in the generation of small
peptides and free amino acids related to
fl avor.are representative of most classes of organic
compounds, such as aldehydes, alcohols,
hydrocarbons, pyrazines, ketones, esters, lac-
tones, furans, sulfur, chloride compounds,
and carboxylic acids (Buscailhon et al.
1994b ; Flores et al. 1998 ). Some volatile
compounds with important aroma character-
istics, such as pyrazines, sulfi de compounds,
and branched - chain aldehydes, may also
originate from amino acids degradation reac-
tions, but their generation rates may depend
on the processing conditions (Flores et al.
1997 ). The fi nal fl avor of the ham depends
on the specifi c aroma and odor thresholds for
each particular volatile compound.
Safety Aspects
Dry - cured hams usually present low bacterial
counts due to limiting factors, such as its high
salt content; the use of nitrate, which is
reduced to nitrite inside the ham; and the
progressive reduction in water activity.
Nitrite is a powerful inhibitor of the growth
of Clostridium botulinum , but sometimes it
may not reach all the areas inside the ham.
Main spoilage or putrefaction is detected
with a sniffi ng test, usually performed by the
end of the process. This test consists of the
insertion of a small probe to the bones ’ junc-
tion. Any off - fl avor is rapidly sniffed and
detected, indicating some type of spoilage
inside the ham, and thus it must be rejected
for consumption (Parolari 1996 ).
The natural fl ora of ham is composed of
certain lactic acid bacteria, such as L. sakei ,
L. curvatus , and P. pentosaceus , but the
counts are below 10^4. These bacteria have
good exo - proteolytic activity, but their con-
tribution to proteolysis is minimal due to
their low counts. Other bacteria, such as S.
xylosus , have nitrate reductase activity,
which is an important enzyme for the reduc-
tion of nitrate to nitrite. Amines levels are
usually low or even negligible in normal dry -
cured hams, but these levels could rise in
case of spoilage with microorganisms with