Agriculture Reference
In-Depth Information
several blood draining knives (as many as 14) can be
used in a 'carousel' which rotates synchronously with the
bleeding conveyor. Arrangements must be made for rou-
tine sterilisation of the knives and adequate staff to man
this additional operation.
The hollow knife is made of stainless steel in two sizes,
for cattle and pigs. Various designs are available, but they
usually consist of a tubular handle with a deflector plate
and two blades set at right angles to each other. They are
easy to strip for sharpening and cleaning and are com-
bined with an anticoagulant dispensing tube. The broad
blade should be directed in the longitudinal direction of
the animal. A suitable form of tubing, for example, made
of collagen, connects the knife to containers where the
blood is cooled prior to collection.
A system which correlates each batch of blood to the
carcase from which it originates must be operated so that
if a carcase is subsequently condemned the blood from
that animal may also be condemned.
The bleeding trough for sheep and pigs should prefer-
ably be enclosed on both sides as for cattle and have a
width of 1.1-1.2 m with the overhead bleeding rail 2.7 m
high, and dressing rails 2.3 m high for sheep and 3.4 m
high in the case of pigs.
and possess high-impact and non-slip properties to aid
the work of the operative who must enter this high-risk
area to apply a shackle for hoisting. Efficient shackling and
hoisting is important to assist rapid bleeding especially if
the animal has only been stunned rather than killed.
A raised sturdy frame of expanded metal onto which
the animal is ejected aids cleanliness and reduces
wetness. This is important since every animal slaughter
comes into direct contact with this area. Consequently,
one animal with a dirty hide has the potential to con-
taminate the hide of many subsequent animals.
Bleeding area
No meat plant should be built without careful considera-
tion being given to the full utilisation of by-products,
edible and inedible. Edible blood must be stored under
refrigeration at a maximum temperature of 3°C.
The
bleeding trough
should be at least 1.5 m wide and
possess a good gradient, side walls of the same height and
two drains, one for blood only and the other for water
when cleansing only. The length of the bleeding line will
depend on the throughput and the system of conveying
carcases but should be generous, since the majority of
blood flow requires 6-8 minutes. The bleeding trough
has two points for the reception of blood: one at the actual
point of sticking where the greater volume of blood will
be handled and thereafter a longer gradual slope that col-
lects 'drip' blood classed as inedible. The overhead bleed-
ing rail should be about 4.9 m above the floor of the dry
landing area, dressing rails about 3.4 m high. The bleed-
ing trough must have a smooth impervious surface, often
a suitable grade of stainless steel. It should be fitted with a
double drain - one opening for the blood to be pumped
to a tanker for disposal and the other for wash water.
Various systems of hygienic bleeding of livestock, mostly
cattle and pigs, are in use, and these may or may not be
combined with an in-plant blood processing department.
The specialised nature of blood processing, as with inedi-
ble by-product processing, means that it may be more sat-
isfactory to collect these items efficiently and then consign
them to an outside central plant for final processing.
Consideration should be given to the size and siting of
the sticking knife wash and sterilising facility. The stick-
ing operative must use one knife for the initial skin cut
and another for severing the blood vessels in order to
minimise the risk of introducing contamination.
For hygienic bleeding for edible purposes,
the stainless
hollow knife
combined with cleanliness and a sodium
citrate/phosphate anticoagulant is used. The knife is held
in the wound by hand, by a rotating endless screw or
by other means. For low throughput slaughter establish-
ments, individual containers are used for holding the
blood; with large throughputs and high rates of slaughter,
Cattle carcase dressing
Following bleeding, carcase dressing may commence only
when the absence of signs of life of the animal has been
verified (Council Regulation No. 1099/2009, Annex III,
para 3.2). If the throughput for cattle slaughter is less than
10/hour, 'cradle dressing' may be the technique of choice.
The cradle should be of high specification stainless steel
construction, robust and easily cleaned with solid polyu-
rethane wheels. However, in most modern slaughter facil-
ities, some form of line dressing is the norm.
Hindleg, hide removal, evisceration, carcase splitting,
inspection, kidney and channel fat removal and carcase
washing stations must have platforms at suitable posi-
tions and heights for operatives and inspectors to work
efficiently and without unnecessary stooping and labour
(Chapter 14 for more detail on Health and Safety).
Working platforms should be of corrosive-resistant
metal, with ducted drainage from the floor and hand,
apron washing and knife sterilising facilities. For safety
reasons, the edge of the platform should be provided
with upraised edges, toe bars and guard rails as required.
Of particular importance is the position of the
viscera
inspection table
, especially for adult cattle, where the top of
the moving-top table should be about 2.7 m from the top of
the conveyor rail and the vertical centre of the carcase posi-
tioned at the edge of the viscera inspection table (1.5 m
wide). A hydraulically powered skip arrangement may be
required to dump the gut onto the viscera inspection table.
