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Where Does Cat Food Come
From? - The Rendering Process
Most pet food comes
from multinational companies which also own human
food concerns. This allows them to profitably use
waste products from the human food chain. Many pet
food manufacturers use good quality ingredients,
others do not. Unless they own and control their
own rendering plants, they are dependent on the
quality controls and integrity of rendering
facilities.
The raw materials
e.g. carcasses are rendered. This is the process
of processing raw animal material on an industrial
scale to remove moisture and fat (note: some
rendering plants produce a meat slurry rather than
a dry product). Some rendering plants are linked
to a particular kind of slaughterhouse; e.g. those
near poultry processing plants may deal
exclusively with poultry by-products, some specialize
in fish products.
In the USA,
independent renderers process raw material from
small packing houses, supermarkets, etc; packer
renderers process raw material from only the
species they are slaughtering, poultry processors
process poultry by-products while protein blenders
purchase and dry rendered tankage from the
preceding processors as a the raw material for
their own process.
The raw product is
blended in order to maintain a certain ratio
between the contents e.g. animal carcasses and
supermarket rejects. The carcasses are loaded into
a stainless-steel pit or hopper and an
auger-grinder at the bottom grinds up the
ingredients into small pieces. It is a larger
version of the old table-clamped meat grinder used
in the days before food processors. The pieces are
taken to another grinder for fine shredding.
The
shredded material is cooked at 280 Fahrenheit for
60 minutes (US figures, those in Britain and
Europe may differ). Meat melts off of bones to
produce a soup or slurry. Yellow greasy fat or
tallow rises to the top and is skimmed off. Some
pet food manufacturers use this slurry. Otherwise,
the cooked meat and bone go to a press, which
squeezes out the remaining moisture and pulverizes
the product into a gritty powder. The grit is
sifted to remove excess hair and large bone chips.
The end products are yellow grease, meat and bone
meal.
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