الفهرس 
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Abstract
This experiment was designed for improvement of broiler chicken breast quality. A total of one hundred fresh broiler breasts (each breast was divided into 4 parts of average weight 150 gm) were purchased from a poultry shop in Beni-Suef City, Egypt. Then the samples were wrapped in sterile polyethylene bags and directly transferred to the laboratory in sterile icebox with a minimum of delay for further preparation.
The collected samples were divided into:
1-Treatment and chilled storage:
A total of 231 broiler chicken breast samples were divided into the following groups:
Control, and treated with either sodium hypochlorite (20, 50 ppm) solutions , trisodium phosphate (8%,10%,), lactic acid (1% , 2 % ), nisin (50, 100 µg/ml) solutions, nisin 50 µg/ml solution followed by lactic acid 1% solution, or nisin 100 μg/ml solution followed by lactic acid 1% solution. All groups were packed using polyethylene bags. Each three samples were separately packed. Then, the packages of each group were labeled and stored at 3 ± 1 °C. All groups were examined at zero days then periodically every three days until spoilage.
from the obtained results of sensory evaluation, it was cleared that broiler chicken breast samples became sensory unaccepted 6th, 6th, 9th, 9th,12th, 15th, 15th, 9th, 12th, 15th and 18th day of storage for control and previously mentioned treated groups respectively.
The pH values of control, and treated groups were 6.09, 6, 6.1, 6.57, 6.6, 5.52, 5.47, 6.16, 6.04, 5.57 and 5.7 respectively at zero day of chilled storage. Such values gradually increased during storage to reach 6.56, 6.5, 6.61, 6.92, 6.65, 6.99, 6.62, 6.13, 5.9, 6.13, and 6.14 respectively at 6th, 6th, 9th, 9th, 12th ,15th, 15th, 9th, 12th, 15th and 18th day of storage for control and treated groups respectively.
TBA-RS values in control, and treated groups each constituting 0.148, 0.129, 0.141, 0.186, 0.13, 0.105, 0.099, 0.193, 0.18, 0.111 and 0.110 mg malondialdehyde /kg, respectively at zero day of chilled storage. Such values gradually increased reaching 0.96, 0.75, 0.79, 0.95, 0.94, 1.17, 1.14, 0.88, 0.87, 0.96, and 0.9 mg MDA/Kg respectively at 6th, 6th, 9th, 9th,12th, 15th, 15th, 9th, 12th, 15th and18th day of chilled storage .
TVB-N values in control, and treated groups were 8.62, 9.8, 7.83, 8.73, 7.98, 8.86, 8.86, 8.49, 8.72, 7.28 and 7.46 mg /100 g at zero day of chilled storage. Such values gradually increased to reach 30.9, 28.93, 29.46, 27.4, 28.9 , 30.3, 30.28, 30.8 , 29.8, 26.6 ,and 25.6 mg/100 g at 6th, 6th, 9th, 9th,12th, 15th, 15th, 9th, 12th, 15th and18th day of chilled storage respectively.
Mesophilic counts in control, and treated groups had mesophilic counts were 1x106, 1x106, 3x105, 2x105, 7x104 , 7x104, 4x104, 6×105, 1×105, 3×104 and 1×104 CFU/ g respectively at zero day of chilled storage. Such count increased gradually to reach in the same groups 1x107, 2x107, 1x107, 2x107, 9x106, 2x107, 1x107, 1x107, 1x107, 9x106, and 8 x106 at 6th, 6th, 9th, 9th,12th, 15th, 15th, 9th, 12th, 15th and18th day of chilled storage respectively.
Psychrophilic counts in control, and treated groups were 6×105 ,7×105 , 2×105, 1×105, 6×104 , 3×104, 2×104 , 3×105 , 1×105 , 9×103 and 4×103 CFU/ g respectively at zero day of chilled storage. Such counts gradually increased in the same groups reaching 2×107, 2×107 ,1×107 , 1×107,1×107, 4×107 , 2×107, 1×107 , 9×106 , 1×107 , and 9×106 CFU/ g respectively at 6th,, 6th, 9th, 9th,12th, 15th, 15th, 9th, 12th, 15th and18th day of chilled storage .
coliforms (MPN) in control, and treated groups were 2.28×104,2.09×104, 4.7 ×103 , 1.02×104, 4.7 ×103 , 9.2 ×102, 7.3 ×102 , 1.8×104, 2.5×104, 4.7 ×103 and 4.7 ×103 m.os./g, respectively at zero day of chilled storage. Such count reached in the same groups to 2.26×104, 3.5×104 , 1.5×104 3.37 ×104 , 2.3 ×104, 1.26 ×104 , 1.02 ×104 , 5.7×104 , 4.7×104 , 3.6×103, 3.47 ×103 at 6th, 6th , 9th ,9th ,12th ,15th ,15th, 9th ,12th, 15th and 18th day of storage respectively.
Fecal coliforms (MPN) in control, and treated groups each constituting 1.1 ×104, 1.8 ×104, 1.47×103 , 3.9 ×103, 9.2×102 , 5.5 ×102, 4.9×102, 8.16×103 , 8.4×103 , 1.2×102 and <3 m.os./ g, respectively. Such counts gradually increased reaching 1.1 ×104, 1.4 ×104, 2.86 ×103 , 6.7×103, 5.03 ×103, 7.2 ×103, 5.5×103, 1.8×104, 9.5×103, 2.2×103and 2.05 ×10 3, and m.os/ g respectively at 6th, 6th , 9th , 9th, 12th , 15th, 15th, 9th, 12th, 15th and 18th day of storage.
E.coli (MPN) in control, and treated groups were 2.16 ×103, 4.86 ×102, 1.2 ×102 ,1.2 ×102, 1.2 ×102 ,2.46×102, 1.2 ×102, 2.1 ×102, 1.78×102, <3 and <3 m.os./ g, respectively. Such counts gradually increased reaching 1.28 ×103, 1.5 ×103 , 9.26 ×102, 6.13 ×102 , 6.13 ×102,1.3 ×103 , 9.26×102 , 4×103, 6.5 ×103, 8×102 and 7.46 ×10 2 CFU/ g respectively at 6th, 6th ,9th , 9th,12th ,15th, 15th, 9th, 12th , 15th and 18th day of storage.
Initial S. aureus count of control, and treated groups were 4 ×104, 7×104, 9×103, 8×103, 7×103 , 3×103, 3×103 , 6×103, 3×103, 2×103and 2×103 CFU/ g, at zero day of chilled storage. Such count reached 3×104, 3×104 ,2×103, 2×103 , 1×103 , 5×103 , 2×103 , 2×103, <102, 7×102, 1×103 at 6th, 6th ,9th , 9th ,12th , 15th, 15th, 9th, 12th , 15th and 18th day of storage respectively.
2-Treatment and frozen storage:
A total of 165 broiler chicken breast samples were divided into the following groups:
Control , and treated with either sodium hypochlorite (20, 50 ppm) solutions , trisodium phosphate (8%,10%,), lactic acid (1% 2 % ), nisin (50, 100 µg / ml) solutions, nisin 50 µg / ml solution followed by lactic acid 1% solution, or nisin 100 µg / ml solution followed by lactic acid 1% solution.
All groups were packed using polyethylene bags. Each three samples were separately packed. Then, the packages of each group were labeled and stored at -18°C. All groups were examined at zero days, 3rd, 6th and 9th and 12th months of storage.
from the obtained results of sensory evaluation, it was cleared that control, and all treated groups were accepted at all occasions of examination during frozen storage. Neither off odor nor off taste was detected during examination
The pH values of control, and treated groups were 6.09, 5.99, 6.16, 6.58, 6.60 5.47, 5.44, 6.21, 6.06, 5.65 and 5.72 respectively at zero day of frozen storage. pH values of such groups gradually increased during storage and reached 6.54, 6.49, 6.37, 6.95, 6.99, 6.1, 5.93, 6.48, 6.4, 6.03 and 5.97 respectively at 12th month of frozen storage.
TBA-RS values in control, and treated groups were 0.132, 0.126, 0.138, 0.137, 0.125, 0.095, 0.076, 0.145, 0.161, 0.111 and 0.11mg malondialdehyde /kg, respectively at zero day of frozen storage. Such values increased with storage duration and reached 1.13, 1.38, 0.82, 0.7, 0.63, 0.6, 0.53, 0.7, 0.63, 0.61, and 0.49 respectively at 12th month of frozen storage.
TVB-N in control, and treated groups were 8.73, 8.5, 8.16, 8.6, 8.2, 8.3, 8. 1, 8.5, 8.3, 7.66 and 7.63 mg /100 g, respectively at zero day of frozen and 25.4, 25.2, 21, 21, 19.1,20, 18.6, 23.3, 21, 18.6, 17.6 mg/100 g at 12th month of frozen storage.
Mesophilic counts in control, and treated groups were 1 × 106, 1× 106, 3 × 105, 2x105,7 ×104, 7 × 104, 4 ×104, 6 ×105, 2 ×105, 3 ×104 and 2 × 104 CFU/ g, respectively at zero day of frozen storage. Such count decreased to reach 3×103, 2 ×103, 4×102, 5 ×102, 4 ×102, 3 ×10, <102, 6×102, 8 ×10, <102, and <102 respectively at 12th month of frozen storage.
psychrophilic counts in control, and treated groups were 9 × 105, 9×105 , 3 × 105, 1×105 , 9 ×104, 3 ×105, 4 × 104, 3 ×104, 1 ×105, 2 ×104 and 9 × 103 CFU/ g, respectively at zero day of frozen storage and 5 ×102, 3 ×102, 7×10, 2 ×102, 8 ×102, <102 ,<102 , 2×102 , 3×10, <102, and <102 CFU/ g respectively at 12th month of frozen storage.
coliforms (MPN) in control, and treated groups each constituting 2.09×104, 2.09×104, 4.7 ×103 ,1.02×104, 4.7 ×103 9.26×102, 7.3×102 1.8×104, 1.08×104, 1.1×103 and 9.2×102m.os./ g, respectively, at zero day and 6.7×10,4.8×10, 3.6×10, 3.6×10 ,1.2×10,<3 , <3, 6.7×10, 2.4×10, <3,and <3 respectively at 12th month of storage.
Fecal coliforms (MPN) in control, and treated groups each constituting 7.8×103, 1.8×104, 1.6×103, 3.9×103, 9.26×102, 4.2×102, 3.6×102, 8.1×103, 8.4×103, 2.4×102 and 1.2×102 m.os./ g, respectively, at zero day . Such count decreased gradually to reach 3.66×10, 2.4×10, 1.2×10, 1.2×10, <3, <3, <3, 2.4×10, <3, <3, and <3 respectively at 12th month of frozen storage.
E.coli (MPN) in control, and treated groups each constituting 1.3×103, 4.9×102, 2.4×102, 2.4×102, 1.70×102,1.2 ×102, 1.2×102, 2.1×103, 1.78×103, <3and <3 m.os./ g, respectively at zero day of storage and became un detected (<3) in all groups at 6th ,9th and 12th month of storage .
Staphylococcus aureus count of control, and treated groups were 8×103, 8×103, 6×103 , 5×103, 5×103, 7×102, 3×102 ,7×102, 3×102, < 102 and < 102 CFU/ g respectively at zero day of storage . Such count gradually decreased during frozen storage reaching 3×10, 3×10, 3×10, 3×10, < 102, < 102, < 102, < 102, < 102, < 102 respectively at 12th month of frozen storage.
The effect of some treatment methods on broiler breast quality was detected during chilling and freezing storage. The recommended methods of treatment to prolong the shelf-life of chilled broiler breast were mentioned.