Agriculture Reference
In-Depth Information
covered in salt. The middles are stacked, cut surface up,
for 5 days, after which excess salt is shaken off and the
sides are turned rind up, and left for 2-3 weeks. The
gammons are packed into tanks with salt for 4 weeks.
On removal, all cuts are washed down to remove some
of the salt. They are then hung on racks and singed with
a blowtorch to remove any slime on the surface and
dried overnight, in a room with circulating air at
10-20°C. The bacon produced may then be smoked,
if required, and prepared for dispatch by trimming
the gammons and rolling and placing the middles in
stockinette.
Immediately after pumping, the middle cuts, back and
belly, are vac packed and heat sealed. They are held in
cellars at a temperature below 4°C for at least 48 hours
before going for blast freezing (−6°C for 5 hours), slicing
and packing. The freezing process suspends curing and
assists high-speed slicing.
The gammons, after pumping, are immersed in
traditional tiled or stainless steel tanks of cover brine for
3 days. The cover brine is used for approximately 3 weeks
before it is discarded and is constantly monitored bacte-
riologically. In former times, cover brine was used
indefinitely and was thought to impart unique flavours
to the product.
Alternative dry cure
An alternative type of dry curing entails placing fresh
rindless pork backs on racks, freezing, pressing into
shape, allowing to temper and slicing. As it comes to the
end of the slicing line, the product is sprayed on both
sides with salt and nitrite solution and then packaged.
Curing takes place in the bag, there being not more than
3½% salt in the final product.
Production of cooked hams
Reformed cooked hams are produced from defatted lean
cuts. Following pickle injection, these are tumbled in a
machine that looks like a cement mixer with sharp stain-
less steel blades in a rotating drum or massaged in a 'Bel
Lagan' massager. In general, small pieces of meat are
tumbled
, while large pieces are
massaged
. The machines
rotate for 7 minutes in every hour for 18 hours, moving
the meat around and ensuring that a uniform cure and
colour are attained. The physical action also tenderises
the muscle and aids fast penetration of the curing agent,
thus saving on curing time. The process releases the
albuminous protein myosin from the meat, leaving its
surface in a gelatinous state. When cooked, the meat
binds together, the myosin acting as a seal, aiding water
retention.
When removed from the tumbling or massaging
process, the product may be allowed to rest for up to 24
hours, or it may be immediately further processed.
Large pieces are manually packed into pots with
pressure lids and cooked for 14 hours to a core tempera-
ture of 70°C. Smaller pieces are automatically fed into
presses which extrude the pork into pre-soaked fibrous
casings. These are semi-cooked for 4-5 hours to a core
temperature of 42°C in preparation for slicing and
vacuum packing.
To ensure consistently high quality, a mid-process
analysis is carried out. A random sample of product,
selected from different cuts, is analysed for levels of
nitrite, salt and added water. There is a standard declara-
tion of not more than 10% added water for middles,
backs and streak. Massaged or tumbled product is
allowed up to 20% added water.
Smoking
Smoking of cured pork improves its keeping proper-
ties further, as well as imparting an appetising colour
and flavour. Traditionally, smoking was carried out
over several days in a brick oven with smouldering
oak, hickory or hardwood sawdust and hot ash piled
on the floor.
It is now more common to use an insulated steel cabi-
net enclosing a heat-exchanger system. The cuts to be
smoked are hung on racks and placed in the cabinet,
and the temperature is raised to approximately 32°C for
30 minutes. Smoke, produced by a smoke generator
consisting of a hopper which automatically feeds dry
hardwood sawdust onto a cast iron hotplate, is drawn
into the cabinet for 1-2 hours. It is important to ensure
that the temperature does not rise above 37°C or the fat
may melt.
The chief bacteriostatic and bactericidal substance in
woodsmoke is formaldehyde. The combination of heat
and smoke usually causes a significant reduction in the
surface bacterial population. In addition, a physical
barrier is provided by superficial dehydration, coagula-
tion of protein and the absorption of resinous
substances.
Common defects in cured meat
Traditional dry-cured bacon
Although described as dry cure, some brine is injected
by hand into the eye muscle of the back and deep into
the gammon. Both cuts are then sprinkled with the
dry-cured mixture, which contains nitrite, before being
1
Fiery red areas
are caused by lack of available nitrite -
miscure. This may occur in deep meat cuts.
2
Jelly pockets
are caused by injection of brine into
connective tissue, which it denatures.
