Scientists Working to Reduce Poultry Crop Breaks
By Sharon Durham
May 15, 2001
Two Agricultural Research Service scientists
are helping to reduce the chances that poultry will become contaminated by
disease-causing bacteria during processing.
Physiologist R. Jeff Buhr and agricultural engineer J. Andra Dickens of the
Richard B. Russell Research Center in Athens, Georgia, are currently conducting
research to reduce breakage of the birds crop, a pouch in the neck that
stores undigested feed.
Rupturing of the crop is a significant source of contamination during
processing, because it can harbor pathogens such as salmonella. The crop is
always removed during processing, but it breaks about 25 percent of the time,
spilling its contents into and on the chicken.
Buhr and Dickens found two related factors that have bearing on whether
crops rupture: the direction in which the crop is removed, and the age of the
bird at the time of processing. Both factors determine the amount of pressure
needed to extract the crop.
For four-week-old broilers, the researchers found it took 2.72 kilograms of
pulling pressure to remove the crop, whereas at eight weeks of age, 4.27 kg of
pressure was required--a 157 percent increase.
The standard method of pulling the crop from the carcass through the
thoracic (chest) cavity also requires greater pulling pressure. Buhr and
Dickens found that taking the crop out through the neck resulted in 95 percent
of the crops being removed intact. In contrast, only 64 percent of the crops
removed through the thoracic cavity exited without rupturing.
It is too early to recommend changes to the processing industry because the
laboratory conditions may not carry through to a commercial setting, according
to the scientists. In the laboratory, the crop extractions were done manually
and not in the automated fashion of poultry processors.
But with a 95 percent intact rate when crops were extracted through the
neck, this alternative method should be given consideration in automated
commercial evisceration systems, according to Buhr.
ARS is the chief scientific research agency in the
U.S. Department of Agriculture.
Scientific contacts: R. Jeff Buhr and J. Andra Dickens, ARS Richard
B. Russell Agricultural Research Center, Athens, Ga., phone (706) 546-3339, fax
(706) 546-3633; firstname.lastname@example.org,