For evaluation of the filling and emptying of the alimentary tract, broiler breeder hens were coo... more For evaluation of the filling and emptying of the alimentary tract, broiler breeder hens were cooped and processed over a 2-d period. Hens were fed at 0600 h on d 1 and after access to feed for 0, 2, 4, and 6 h were placed into coops. Half of the hens from each pen were either immediately processed or were held in coops overnight and processed the following morning, d 2. The alimentary tract was excised from the carcass and then separated and weighed in three segments: the crop, proventriculus and gizzard, and intestines. Hens processed on d 1, after access to feed for only 2 h, had attained maximum intestine weight (176 g), but not until after access to feed
chapter two Preslaughter factors affecting poultry meat quality Julie K. Northcutt Contents Intro... more chapter two Preslaughter factors affecting poultry meat quality Julie K. Northcutt Contents Introduction 5 Antemortem factors affecting quality 6 Harvesting ... Under the terms of the contract, the producer (grower) provides land, labor, housing, equipment, utilities, and litter, while the ...
The objective of this study was to determine effects of electrical stunning duration on quality o... more The objective of this study was to determine effects of electrical stunning duration on quality of broiler chicken fillets. Seventy-two broiler chickens were electrically stunned for 0, 2, 4, 6, 8, or 10 s, slaughtered, and chilled. After 1 h post-mortem, both pectoral muscles were excised and cooked. Cooking loss, pH, cooked color values, and shear values were measured. As stunning time increased, pH and shear values significantly increased. Except for a small but significant increase in yellowness, color values were unaffected by stunning duration. Cooking loss was unaffected by stunning duration. These data indicate that stunning duration can affect post-mortem muscle metabolism as measured by pH change. Therefore, control of the process of slaughtering broilers requires careful regulation of stunning duration.
Stunning and slaughter trials were conducted to evaluate the influence of stunning method (electr... more Stunning and slaughter trials were conducted to evaluate the influence of stunning method (electrical 50 V alternating current, CO 2 gas: 0 to 40% for 90 s or 40 to 60% for 30 s) on feather retention force (FRF) in commercial broilers. Feathers from the pectoral, sternal, and femoral feather tracts were sampled with a force gauge before stunning (ante-mortem) and contralaterally either after stunning (peri-mortem from 0.5 to 4 min) or after stunning and bleeding (post-mortem from 2 to 6 min). Prior to stunning, ante-mortem FRF values varied among assigned stunning methods only for the pectoral (7%) feather tract. After stunning, perimortem FRF values were higher only for the sternal tract (11% for 40 to 60% CO 2 for 30 s); whereas after stunning and bleeding, post-mortem FRF values were lower than ante-or peri-mortem only for the sternal tract (10% lower for 40 to 60% CO 2 for 30 s). Peri-and post-mortem FRF values did not differ among stunning methods for the pectoral and femoral feather tracts. Small changes in FRF values occurred from ante-mortem to peri-mortem (-1 to +12%), and from ante-mortem to post-mortem (-2 to +8%) across stunning methods. A significant increase was determined for only the pectoral tract (7%) from ante-to peri-mortem across stunning methods. Electrically stunned broilers that were not bled gained weight in excess of the 36 feathers removed (0.16%), apparently due to body surface water pickup during the brine-stunning process, whereas CO 2stunned broilers lost weight due to excretion of cloacal contents (-0.31 to-0.98%). The change in body weight among stunning methods was significant (P < 0.0233). Peri-and post-mortem FRF, in addition to bleed-out body weight loss, were not substantially influenced by electrical or CO 2 stunning methods, and, therefore, carcass defeathering efficiency may not differ after scalding.
Four experiments were conducted to determine the effects of electrical stunning and decapitation ... more Four experiments were conducted to determine the effects of electrical stunning and decapitation on bird activity as well as carcass and meat quality. In Experiment 1, broilers were subjected to one of four stunning and killing methods: no stun and neck cut, stun and neck cut, no stun and decapitation, and stun and decapitation. Birds were scored for severity of physical activity on a scale of 1 to 4 with 1 being no activity and 4 being severe wing flapping and muscular contractions. Carcasses were also scored for red wing tips and broken bones. In Experiments 2 to 4, all birds were stunned prior to neck cut or decapitation. Carcasses were scored as described in Experiment 1 as well as measurements of blood loss, feather removal, and breast meat pH, color, cook loss, and tenderness. Based on carcass activity in
To compare immersion and spray scalding temperature profiles, thermocouples were positioned benea... more To compare immersion and spray scalding temperature profiles, thermocouples were positioned beneath the skin of broiler carcasses in eight separate locations. The locations were as follows: 1 and 2) the upper left and right breast, 3 and 4) middle of the left and right thigh, 5 and 6) beneath the left and right wing, 7) the lower back above the pygostyle, and 8) the upper back between the wings. Standard immersion scalding at 52 or 56.5 C for 2 min or a prototype spray scalder at 60, 65, or 70 C for 1 min were used to monitor s.c. temperature during scalding. Immersion scalding resulted in an exponential profile with the lower temperature having less temperature deviation for the monitored locations. Among sampling locations, the spray scald temperatures were divergent among locations and the highest temperatures were recorded when thermocouples were within the spray patterns. As with the immersion scalded carcasses, lower temperatures for the spray scalding demonstrated less deviation among the monitored locations and a closer grouping of the final temperatures. The only spray scald temperature tested at which s.c. temperatures approached those of the immersion scalded carcasses was 70 C. Additional carcasses were scalded, picked, and examined for skin appearance and picking efficiency. All carcasses spray scalded for 60 s had a "cooked appearance" when evaluated. When spray scald times were reduced to 30 s, skin appearance improved, but with the exception of the 70 C trial, picking efficiency was poorer.
The objective of this study was to assess effects of treating electrically stimulated broiler for... more The objective of this study was to assess effects of treating electrically stimulated broiler forequarters with polyphosphates after various aging periods on quality. Ninety-six mixed sex broilers were electrically stunned and slaughtered. Half the carcasses were electrically stimulated during bleeding and half were not. Forequarters were harvested immediately after chilling and after 2, 4, and 6 h postchill. Left forequarters were marinated in salt solution and right f o r e q u a r t e r s i n s a l t s o l u t i o n p l u s s o d i u m tripolyphosphate. After marination, the quarters were cooked. Yield and meat pH were evaluated immediately after marinating; and color, yield, and cooking loss were evaluated after cooking. Electrical stimulation resulted in a decline in muscle pH for the 0 postchill group. The pH of muscles from unstimulated and stimulated carcasses from the remainder of the postchill times were equivalent. Phosphate treatment increased pH at all postchill times. Electrical stimulation of the marinated quarters increased cooking loss and decreased yield regardless of marinade composition. Both cooking loss and yield were superior for forequarters harvested at 0 or 2 h postchill compared to those harvested at 4 or 6 h postchill. The phosphate improved moisture binding regardless of electrical treatment or time of harvest. Color values of cooked muscles were unaffected by marination time, but the phosphate-treated muscles had higher b* (yellowness) values than controls. Shear values of unstimulated carcasses that received phosphate treatment were 35% greater than those that received no phosphate treatment. When the carcasses were electrically stimulated, the toughening effect of the phosphate was eliminated.
To determine whether feather retention force (FRF) in 6-wk-old commercial broilers was influenced... more To determine whether feather retention force (FRF) in 6-wk-old commercial broilers was influenced by the presence or absence of cutaneous innervation, nerve trunks for the pectoral and sternal feather tracts were severed unilaterally (left side) in Trial 1. In Trial 2, the sternal subcutaneous nerve trunk was severed either unilaterally (left or right side) or bilaterally. Four days postdenervation, FRF was determined bilaterally either antemortem (immediately prior to stunning) or 2 min after stunning and bleeding (postmortem). In Trial 1, the pectoral feather tract ante-and postmortem FRF values did not differ significantly for innervated or denervated tracts. In this trial, the sternal feather tract ante-and postmortem FRF values were 13% higher (44 g) for the denervated (left side) than for the innervated (right side) treatments. Partitioning this difference into the effects of sample side or innervation could not be attained because only the left side was denervated (left-denervation or right-innervated) in Trial 1. In Trial 2, both the left and right sternal feather tracts were represented in equal numbers for the innervated and denervated treatments, and there were no significant differences in FRF related to innervation, left and right side, or ante-and postmortem sample times. The presence or absence of cutaneous nerve innervation does not appear to influence FRF ante-or postmortem. This finding indicates that treatments disabling the central nervous system antemortem may lower FRF indirectly by altering cutaneous metabolism and therefore have been consistently unsuccessful in substantially altering postmortem FRF.
For evaluation of the filling and emptying of the alimentary tract, broiler breeder hens were coo... more For evaluation of the filling and emptying of the alimentary tract, broiler breeder hens were cooped and processed over a 2-d period. Hens were fed at 0600 h on d 1 and after access to feed for 0, 2, 4, and 6 h were placed into coops. Half of the hens from each pen were either immediately processed or were held in coops overnight and processed the following morning, d 2. The alimentary tract was excised from the carcass and then separated and weighed in three segments: the crop, proventriculus and gizzard, and intestines. Hens processed on d 1, after access to feed for only 2 h, had attained maximum intestine weight (176 g), but not until after access to feed
chapter two Preslaughter factors affecting poultry meat quality Julie K. Northcutt Contents Intro... more chapter two Preslaughter factors affecting poultry meat quality Julie K. Northcutt Contents Introduction 5 Antemortem factors affecting quality 6 Harvesting ... Under the terms of the contract, the producer (grower) provides land, labor, housing, equipment, utilities, and litter, while the ...
The objective of this study was to determine effects of electrical stunning duration on quality o... more The objective of this study was to determine effects of electrical stunning duration on quality of broiler chicken fillets. Seventy-two broiler chickens were electrically stunned for 0, 2, 4, 6, 8, or 10 s, slaughtered, and chilled. After 1 h post-mortem, both pectoral muscles were excised and cooked. Cooking loss, pH, cooked color values, and shear values were measured. As stunning time increased, pH and shear values significantly increased. Except for a small but significant increase in yellowness, color values were unaffected by stunning duration. Cooking loss was unaffected by stunning duration. These data indicate that stunning duration can affect post-mortem muscle metabolism as measured by pH change. Therefore, control of the process of slaughtering broilers requires careful regulation of stunning duration.
Stunning and slaughter trials were conducted to evaluate the influence of stunning method (electr... more Stunning and slaughter trials were conducted to evaluate the influence of stunning method (electrical 50 V alternating current, CO 2 gas: 0 to 40% for 90 s or 40 to 60% for 30 s) on feather retention force (FRF) in commercial broilers. Feathers from the pectoral, sternal, and femoral feather tracts were sampled with a force gauge before stunning (ante-mortem) and contralaterally either after stunning (peri-mortem from 0.5 to 4 min) or after stunning and bleeding (post-mortem from 2 to 6 min). Prior to stunning, ante-mortem FRF values varied among assigned stunning methods only for the pectoral (7%) feather tract. After stunning, perimortem FRF values were higher only for the sternal tract (11% for 40 to 60% CO 2 for 30 s); whereas after stunning and bleeding, post-mortem FRF values were lower than ante-or peri-mortem only for the sternal tract (10% lower for 40 to 60% CO 2 for 30 s). Peri-and post-mortem FRF values did not differ among stunning methods for the pectoral and femoral feather tracts. Small changes in FRF values occurred from ante-mortem to peri-mortem (-1 to +12%), and from ante-mortem to post-mortem (-2 to +8%) across stunning methods. A significant increase was determined for only the pectoral tract (7%) from ante-to peri-mortem across stunning methods. Electrically stunned broilers that were not bled gained weight in excess of the 36 feathers removed (0.16%), apparently due to body surface water pickup during the brine-stunning process, whereas CO 2stunned broilers lost weight due to excretion of cloacal contents (-0.31 to-0.98%). The change in body weight among stunning methods was significant (P < 0.0233). Peri-and post-mortem FRF, in addition to bleed-out body weight loss, were not substantially influenced by electrical or CO 2 stunning methods, and, therefore, carcass defeathering efficiency may not differ after scalding.
Four experiments were conducted to determine the effects of electrical stunning and decapitation ... more Four experiments were conducted to determine the effects of electrical stunning and decapitation on bird activity as well as carcass and meat quality. In Experiment 1, broilers were subjected to one of four stunning and killing methods: no stun and neck cut, stun and neck cut, no stun and decapitation, and stun and decapitation. Birds were scored for severity of physical activity on a scale of 1 to 4 with 1 being no activity and 4 being severe wing flapping and muscular contractions. Carcasses were also scored for red wing tips and broken bones. In Experiments 2 to 4, all birds were stunned prior to neck cut or decapitation. Carcasses were scored as described in Experiment 1 as well as measurements of blood loss, feather removal, and breast meat pH, color, cook loss, and tenderness. Based on carcass activity in
To compare immersion and spray scalding temperature profiles, thermocouples were positioned benea... more To compare immersion and spray scalding temperature profiles, thermocouples were positioned beneath the skin of broiler carcasses in eight separate locations. The locations were as follows: 1 and 2) the upper left and right breast, 3 and 4) middle of the left and right thigh, 5 and 6) beneath the left and right wing, 7) the lower back above the pygostyle, and 8) the upper back between the wings. Standard immersion scalding at 52 or 56.5 C for 2 min or a prototype spray scalder at 60, 65, or 70 C for 1 min were used to monitor s.c. temperature during scalding. Immersion scalding resulted in an exponential profile with the lower temperature having less temperature deviation for the monitored locations. Among sampling locations, the spray scald temperatures were divergent among locations and the highest temperatures were recorded when thermocouples were within the spray patterns. As with the immersion scalded carcasses, lower temperatures for the spray scalding demonstrated less deviation among the monitored locations and a closer grouping of the final temperatures. The only spray scald temperature tested at which s.c. temperatures approached those of the immersion scalded carcasses was 70 C. Additional carcasses were scalded, picked, and examined for skin appearance and picking efficiency. All carcasses spray scalded for 60 s had a "cooked appearance" when evaluated. When spray scald times were reduced to 30 s, skin appearance improved, but with the exception of the 70 C trial, picking efficiency was poorer.
The objective of this study was to assess effects of treating electrically stimulated broiler for... more The objective of this study was to assess effects of treating electrically stimulated broiler forequarters with polyphosphates after various aging periods on quality. Ninety-six mixed sex broilers were electrically stunned and slaughtered. Half the carcasses were electrically stimulated during bleeding and half were not. Forequarters were harvested immediately after chilling and after 2, 4, and 6 h postchill. Left forequarters were marinated in salt solution and right f o r e q u a r t e r s i n s a l t s o l u t i o n p l u s s o d i u m tripolyphosphate. After marination, the quarters were cooked. Yield and meat pH were evaluated immediately after marinating; and color, yield, and cooking loss were evaluated after cooking. Electrical stimulation resulted in a decline in muscle pH for the 0 postchill group. The pH of muscles from unstimulated and stimulated carcasses from the remainder of the postchill times were equivalent. Phosphate treatment increased pH at all postchill times. Electrical stimulation of the marinated quarters increased cooking loss and decreased yield regardless of marinade composition. Both cooking loss and yield were superior for forequarters harvested at 0 or 2 h postchill compared to those harvested at 4 or 6 h postchill. The phosphate improved moisture binding regardless of electrical treatment or time of harvest. Color values of cooked muscles were unaffected by marination time, but the phosphate-treated muscles had higher b* (yellowness) values than controls. Shear values of unstimulated carcasses that received phosphate treatment were 35% greater than those that received no phosphate treatment. When the carcasses were electrically stimulated, the toughening effect of the phosphate was eliminated.
To determine whether feather retention force (FRF) in 6-wk-old commercial broilers was influenced... more To determine whether feather retention force (FRF) in 6-wk-old commercial broilers was influenced by the presence or absence of cutaneous innervation, nerve trunks for the pectoral and sternal feather tracts were severed unilaterally (left side) in Trial 1. In Trial 2, the sternal subcutaneous nerve trunk was severed either unilaterally (left or right side) or bilaterally. Four days postdenervation, FRF was determined bilaterally either antemortem (immediately prior to stunning) or 2 min after stunning and bleeding (postmortem). In Trial 1, the pectoral feather tract ante-and postmortem FRF values did not differ significantly for innervated or denervated tracts. In this trial, the sternal feather tract ante-and postmortem FRF values were 13% higher (44 g) for the denervated (left side) than for the innervated (right side) treatments. Partitioning this difference into the effects of sample side or innervation could not be attained because only the left side was denervated (left-denervation or right-innervated) in Trial 1. In Trial 2, both the left and right sternal feather tracts were represented in equal numbers for the innervated and denervated treatments, and there were no significant differences in FRF related to innervation, left and right side, or ante-and postmortem sample times. The presence or absence of cutaneous nerve innervation does not appear to influence FRF ante-or postmortem. This finding indicates that treatments disabling the central nervous system antemortem may lower FRF indirectly by altering cutaneous metabolism and therefore have been consistently unsuccessful in substantially altering postmortem FRF.
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