Controlled-atmosphere stunning
Welfare-conscious groups have issued studies suggesting that controlled-atmosphere stunning of poultry is more humane than electrical stunning of birds. Quick-ser-vice restaurant chains, such as Wendy’s International, Inc. and Burger King Corp.,
have announced a purchasing preference for poultry meat from harvest plants that utilize controlled-atmosphere stunning rather than the traditional method of live-hang-ing birds upside down by the legs and electrically stunning them. Controlled-atmosphere stunning of pigs versus restraint and electrical stunning has also reduced
overall stress. There is a reduction in animal stress in large, CO -stunning systems, as
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the animals can be moved in small groups rather than individually, without the need
for restraint. Plants utilizing CO -stunning systems report a lower incidence of PSE,
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bruising and blood splash in the meat.
GLOBAL SUCCESS STORIES
The true benefits of humane handling are most easily measured by just that:
measuring. Below are examples of how the awareness, education and auditing of the process
has resulted in meat quality, food safety and humane handling improvements.
Controlled-atmosphere
stunning of turkeys
In 2000, the Michigan Turkey Producers
Co-op Incorporated
(MTP) opened a state-of-the-art processing
plant to harvest locally
grown turkeys. The
company utilizes an
automated catching
and conveying system
that moves groups of
turkeys into transport
crates without the need
Figure 1: Percent of Whole-bird Samples Testing Positive for
for hand catching. The
Salmonella at MTP
plant uses a controlled-atmosphere stunning (CAS) system that utilizes CO to stun
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birds while still housed in large group containers, again eliminating the need for
human handling. This method of harvest is considered more ergonomically safe for
the employees, who do not need to handle heavy, live birds, and also provides food-safety benefits. Animal stress is minimized as the birds are not handled by humans
until after stunning is completed. The Salmonella performance data for over 200 MTP
tests shows a rate of 1.43% positive (Figure 1). This rate is 76% lower than 2007 USDA
data for Salmonella performance tests of turkey carcasses ( 6.2%). The use of CAS also
provides improvements in PSE and meat color as well as a higher deboning yield, decreased bruising, lower incidence of broken wings and fewer blood spots in the meat.
Improved handling of pigs
The Pronaca pork plant in Ecuador
was experiencing internal muscle bruising, capillary rupture and PSE on the
1,000 pigs that were processed each day.
In April of 2007, a humane-handling
team was developed and trained. The
team determined that improvements in
transport, truck unloading and animal
cooling, as well as gentle handling and
the elimination of distractions, could
dramatically improve the meat products.
Weekly humane-handling audits measured the effect of each change and
clearly demonstrated the value of the
team’s efforts. Measurement of key meat
parameters showed an increase in muscle pH and a substantial reduction in
economic losses due to meat-drip loss
(Figure 2).
Poultry handling measures
Pipasa is probably the largest, most
recognized poultry supplier in Costa
Rica. In March of 2005, the company
had yet to fully embrace the benefits of
humane handling. In a country where
warm days can mean temperatures of
+ 32 °C, cooling of the birds during
holding is critical. Overheating can
cause heat stress, dehydration and possibly even premature death. Some fans in
the truck-holding area and receiving
dock were not working efficiently and
not all of the misters were operating effectively. In some areas, birds were observed panting and showed signs of heat
stress. There is an economic advantage
to having a good cooling system for reducing bird stress, yield loss and improving meat quality. This was communicated to the team at Pipasa.
Initially, the plant had some challenges with the stunning system inconsistently stunning the birds. This
Preparing pigs for transport
Kowi, a pork operation in Mexico, measured several meat parameters and determined that the amount of PSE in finished meat varied
by farm. When the lowest PSE farms were asked about their procedures, it was discovered that the day prior to transport, the pigs were
moved to a staging pen. This familiarized the animals with movement to a new environment, prior to transport, greatly reducing the
stress associated with truck loading and transport. Also, the harvest
plant’s animal-handling operators received training to assure calm
handling, and the CO -stunning system was modified to improve an-
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imal movement. The result was a decrease in drip loss and PSE for
pork products.
Figure 2: Pronaca Pork Key Meat Parameters
