الفهرس 
Incidence and public health hazards of CPSA and E. coli in chicken meat e
Material and MethodsOnly 14 pages are availabe for public view
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Abstract
In the present study, 150 random samples of fresh and frozen chicken
meat (breasts, thigh and fillet) were collected from various shops, supermarkets
and slaughtered house in Sohag city, Egypt. The samples were tested for the
presence of S. aureus, and E.coli (E.coli O157:H7). The isolated strains were
identified by conventional method and then confirmed by PCR. Moreover, CNE
and RNE were prepared and then characterized by Zeta sizer, FTIR and TEM.
Finally, the Ch films loaded with CNE and RNE were prepared and mechanical,
physical properties, Surface color parameters and transparency of the films were
studied and the effect of different prepared films on the growth and
multiplication of CPSA during refrigerated storage of chicken meat at 4°C was
studied. Finally, sensory evaluation of the chicken meat treated with Ch-based
nano-emulsions films was studied.
All samples were submitted for bacteriological examination. First, by
conventional culture method, CPSA was isolated in percentages 48, 24 and 6%
of chicken thighs, chicken breast and chicken fillet, respectively and noted that
the presence of CPSA in fresh products (40%) is more than that in frozen ones
(12%) in all samples. The isolates subjected to biochemical tests and confirmed
by PCR technique using 23S rRNA geneand. The results revealed that (100%) all
isolates were positive to 23S rRNA gene and confirmed to be S. aureus.
The obtained results revealed that by conventional culture method, 37
(24.6%) out of 150 examined chicken meat samples collected from thigh, breast
and fillet were contaminated with E. coli, (13/25) 52%, (10/25) 40% and (7/25)
28% of examined fresh chicken and (5/25) 20%, and (2/25) 8% of examined
frozen chicken of thigh, and breast, respectively. While in fillet samples, it was
not detected.
Summary
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Also, the isolates subjected to biochemical tests and 33 out of 37
(89.2%) E. coli isolates were S.F, while 4 out of 37 (10.8%) E. coli isolates
N.S.F who suspected to be E. coli O157:H7. the incidence of N.S.F. E. coli was
2.6% (4/150) from the total examined chicken meat samples and (4/37)10.8 %
from total E. coli isolates. The four isolates of N.S.F E. coli which detected in
chicken meat were submitted to PCR for detection H7 gene and results indicated
that none of the isolates contained H7 gene.
The study included preparation and characterization of CNE and RNE.
Results of NEs characterization showed that The CNE and RNE were
characterized by zeta-sizer and the PDI were 0.32 and 0.21 with average
dynamic nano-meter 54.56, 44.98 nm for both respectively. In addition to, FTIR
analysis of the prepared NEs suggested that there were changes occurred in the
functional groups of EOs, which were due to NEs formation.
In the present study, MIC of CNE and RNE was determined against
isolated strain of CPSA by measuring zones of inhibition and then used to
prepare in packaging. Results showed that the MIC for CNE was detected at
1.56 and 0.78% with inhibitory zone 15.77±0 and 12.17±0.14 mm while, RNE
at 1.56 and 0.78% were 14.9±0.01 and 11.17±0.02 mm, respectively.
The MIC (0.78 and 1.56%) of CNE and RNE were adjusted in Ch
prepared based films and tested for physical, chemical and biological properties.
The film had nice mechanical performance and water/CO2 permeability.
The antibacterial activity of the prepared films was tested against CPSA
inoculated in chicken meat products and stored at refrigeration temperature.
Furthermore, results showed that illustrated the significant decrease (P<0.01) in
CPSA count at 4th day of storage in 4oC in samples packaged by Ch-CNE
Summary
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(1.56%) films with complete eradicated to the CPSA at 7th day of storage in
comparing with other films.
In addition, all NEs-Ch films have good pH ranged from 5.4 to bad pH
6.4 at 7-9th day of storage except Ch-CNE films were 5.8 at 12th day. The Ch-
CNE (0.78%) and Ch-RNE (1.56%) were completely reduced the CPSA
inoculated chicken samples at 9th days, while Ch-RNE (0.78%) was at 12th day.
During the storage period, the samples wrapped by Ch-CNE (1.56%)
films showed significantly good organoleptic conditions and without any bad
texture or appearance with highest OAA (4±0) and good pH 5.8 until 12th day.
All other wrapped samples were good in organoleptic and OAA with significant
difference with un-wrapped samples but nearly no difference between each
other.The prepared packaging films with NEs allow longer storage at
refrigerated temperatures (4 °C) reach to 14 days.
Moreover, our results were supported by microbiological and sensory
evaluation and it can be emphasized that the nanocomposite film has the ability
to delay microbial, extend the shelf-life and exhibit desirable sensory attributes
including taste, color, odor, texture and overall acceptability in chicken meat.
The CNE (1.56%) incorporated with Ch-based films improve the antibacterial
activity of the films against CPSA and complete eradicated at 7th day of
refrigerated storage. It was extended the shelf-life of raw chicken meat
inoculated with CPSA to reach 12 days.