Cured Meat Products
Practical Action
1) Curing: Bacon and Ham
Bacon is made from the back, belly and loin cuts of pork, whereas ham and gammon are made
from the front or hind quarters. The meat is cured either by dry-salting or in brine. It can be
unsmoked or smoked and is usually refrigerated for retail sales. Dry-salting is less common, but
involves rubbing fine salt onto the surface of the meat repeatedly over several weeks to make
ham. Alternatively, pieces of meat can be ‘tumbled’ with the salt mixture in a tumbling machine
that is similar to a butter churn (see Technical Brief: Butter and Ghee). Typically this would be
for 30 - 60 mins every 24 hours or for 5 -10 mins every 8 hours.
The simplest method of brine curing involves placing deboned cuts of pork so that they are fully
submerged in a tank of refrigerated brine (below 5oC) for five days, turning them occasionally.
The brining tank should be constructed from stainless steel, food-grade plastic or concrete lined
with ceramic tiles and waterproof grouting. The brine typically contains 25 kg salt, 3 kg sodium
nitrate and 50g sodium nitrite per 100 litres of water. Ham and ‘sweet-cure’ bacon brines may
also contain sugar, and other specialist brines may contain a variety of herbs and spices,
including juniper berries, nutmeg, cloves, peppercorns, rosemary or bay leaves. Further details
are given in Opportunities in food processing.
The brine causes water to pass out of the meat and as a
result the strength of the brine falls as it becomes more
diluted. The strength is checked daily using a ‘salometer’
(see QA below), and curing salts are added to maintain the
brine strength. Once curing is completed, the brine should be
discarded and a new batch prepared for the next meat.
More rapid curing can be achieved by injecting the meat with
brine before tank curing. This brine is slightly stronger and
contains 30 kg salt per 100 litres of water and the same
amount of sodium nitrite/nitrate as tank brine. The meat
should be injected in about 20 places, deep into the meat,
which causes the meat to increase in weight by 8 -10%. At
larger scales of operation an electric injection pump (Fig. 3)
that has 5 - 10 needles can be used. After injecting the
brine, the meat is cured in a tank as above.
Figure 3: Brine injection
needles. Photo from Cyborg
Equipment Corporation
After curing, the meat is allowed to dry and mature under
refrigeration at below 5oC for approximately 5 - 7 days.
The humidity in the room should be kept at
approximately 85% by keeping the floor wet with
saturated brine (not water) at all times (saturated brine
gives an air humidity of 75%). Bacon is then sliced to
the required thickness using a manual or electric meat
slicer (Fig. 4.). It can be wrapped in greaseproof paper if
it is sold quickly, or sealed in either plastic bags or
plastic trays with heat-sealed plastic covers. It is stored
under refrigeration for retail display for about 2 -3 weeks.
Vacuum packing extends the shelf life further, but
vacuum packing machines are expensive to buy and to
maintain, and they are only suitable for processors that
can justify the expense with high levels of profitability.
Figure 4: Bacon Slicer. Photo
from ProCook
Cured hams are cooked by either roasting, or by boiling
in sealed plastic pouches. The internal temperature should reach at least 70oC, with the cooking
time approximately one hour for each kg in weight of ham. They are then sliced and packaged in
a similar way to bacon. NB: because cooked ham is eaten without further cooking, it is essential
that strict hygiene is enforced to prevent contamination of the meat after cooking. This is
therefore a product that should only be produced by experienced meat processors.
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