الفهرس 
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Abstract
The safety and quality of different flavors ice creams and frozen yoghurt samples sold at Alexandria city were investigated. Samples were collected randomly from different shops, supermarkets and street vendors in Alexandria governorate. Egypt from February 2017 to June 2017.
7.1. Chemical evaluation of examined frozen dairy dessert:
7.1.1. Determination of the fat content
Mean value for fat content were (8.19±0.81), (8.91±1.27), (14.28±2.05), (4.29±1.26) and (11.67±3.04) in examined vanilla, chocolate, mango, strawberry ice creams and frozen yoghurt samples, respectively.
7.1.2. Determination of the solid not fat content:
Mean value of solids not fat content were (36.55±2.54), (41.99±5.28), (40.58±6.34), (19.50±2.57) and (34.10±3.49) in examined vanilla, chocolate, mango, strawberry ice creams and frozen yoghurt samples, respectively.
7.1.3. Determination of protein content:
Mean value of protein content in examined vanilla, chocolate, mango, strawberry ice cream samples and frozen yoghurt were (13.76±.97),(15.63±1.84),(15.15±2.31),(7.63±.92) and (12.77±1.34),repectively.
7.1.4. Determination of lactose content
Mean value of lactose content in examined vanilla, chocolate, mango, strawberry ice creams and frozen yoghurt samples were (19.74±1.36), (23.21±2.93), (22.33±3.57), (11.17±1.33) and (17.76±2.13); respectively.
7.2. Sanitary evaluation by grading of examined frozen dairy dessert samples:
7.2.1. Methylene Blue Reduction Test (MBRT)
MBRT ice cream samples over 4 hours (Grad 1): 15(75%), 10(50%), 7(35%) and 2(10%) of examined of vanilla, chocolate, mango and strawberry ice cream samples were Grade (1), respectively.
MBRT ice cream samples grad 2: 2(10%), 1(5%), 0(0%) and 1(5%) of examined vanilla, chocolate, mango and strawberry ice creams; respectively were Grade (2) with a good quality.
MBRT ice cream samples grad 3: 2(10%), 2(10%), 6(30%) and 2(10%) of examined vanilla, chocolate, mango and strawberry ice creams, respectively were Grade (3) with poor quality.
MBRT for ice cream samples grad 4(reduction time less than 30 minutes): 1(5%), 7(35%), 7 (35%) and 15(75%) of examined vanilla, chocolate, mango and strawberry ice creams; respectively which were Grade (4) with a bad quality.
MBRT for frozen yoghurt: 17(85%) of examined of frozen yoghurt samples showed Grade (4); 3(15%) showed grade (3).
7.3. Microbiological evaluation of the examined frozen dairy dessert samples:
7.3.1. Aerobic Mesophilic Plate Count (cfu/g):
Mean values of aerobic mesophilic plate count were 1.5x〖10〗^5±6.1x〖10〗^4, 9.5x〖10〗^6± 6.4x〖10〗^5, 4.8x〖10〗^6±2.4x〖10〗^6, and 5.1x〖10〗^7±1.8x〖10〗^7, of examined vanilla, chocolate, Mango and strawberry ice cream samples, respectively.
7.3.2. Coliforms count(cfu/g):
Mean values of Coliforms count of examined vanilla, chocolate, mango, strawberry ice creams and frozen yoghurt samples were 2.5x〖10〗^2±7.1x10, 6.6〖x10〗^2±2.5x〖10〗^2, 9.9x〖10〗^3±6.3x〖10〗^3, 4x〖10〗^3±1.4x〖10〗^3 and 1.5x〖10〗^2 ± 2.9x10, respectively.
Frequency distribution of isolated Coliforms from examined flavored ice cream with vanilla, chocolate, mango and strawberry were Citrobacter diverses (16.67, 20, 15 and 10%), Citrobacter freundii (8.33, 13.33, 5 and 10%), Enterobacter cloaca (25, 20,15 and 25%), Enterobacter aerogenes (8.33, 13.33, 15 and 10%), Enterobacter agglumerans (8.33, 13.33, 5 and 5%), Escherichia coli (0, 6.67, 10 and 15%), Klebsiella spp. (25, 6.67, 30 and 15%) and Serratia liquifaciens (8.33, 6.67, 5 and 10%), respectively.
Frequency distribution of isolated Coliforms in examined frozen yoghurt samples were; Citrobacter diverses, Citrobacter freundii, Enterobacter cloaca, Enterobacter aerogenes, Enterobacter agglumerans, Escherichia coli, Klebsiella spp. and Serratia liquifaciens in frozen yoghurt samples were (12.50, 6.25, 18.75, 12.50, 12.50, 6.25, 25 and 6.25%), respectively.
Serodaignosis of isolated E. coli from positive samples of examined frozen dairy desserts were 2(22.22%) O111: H2 (Enterohaemorrhagic E coli), 1(11.11%) O127: H6 (Enterotoxigenic E coli), 2(22.22%) O26:H11 (Enterohaemorrhagic E. coli), 1(11.11%) O55: H7 (Enteropathogenic E coli) and 1(11.11%) O91: H21 (Enterohaemorrhagic E coli); while there were 2 (22.22%) could not be identified.
Incidence of virulence gene of enteropathenic E.coli using multiplex PCR showed that 2 strains (100%) samples of E. coli O26 : H11 were Positive E. coli strains for Stx1, Stx2 and eaeA; 1 strain of E. coli O55 : H7 was positive for Stx2 gene only; 1 strain of E. coli O91 : H21 was Positive for Stx1 and Stx2 genes; 2 strains of E. coli O111 : H2 was Positive for Stx1, Stx2 and eaeA genes, while the other strain was Positive only for Stx1 and Stx2 genes, Finally 1 strain of E. coli O127 : H6 was Positive for Stx1gene.
7.3.3. Staphylococcus aureus Count (cfu/g):
Mean values of Staphylococcus aureus count in examined vanilla, chocolate, mango, strawberry ice creams and frozen yoghurt were 1.6x〖10〗^2±7.0x10, 3.4x〖10〗^2±9.4 x10, 1.9x〖10〗^3±1.5x〖10〗^3, 7.4x〖10〗^2±2.9x〖10〗^2, and 3.33x〖10〗^2±1.2x〖10〗^2(cfu/g), respectively.
7.3.4. Total mold count and identification of the isolated mold strains:
Mean values of mold count (cfu/g) in the examined vanilla, chocolate, mango, strawberry ice creams and frozen yoghurt samples were 2.2x〖10〗^2±8.4x10, 9.6x〖10〗^2±4.4x〖10〗^2, 3.2x〖10〗^3±1.3x〖10〗^3, 3.7x〖10〗^3±1x〖10〗^3 and 1.3x〖10〗^4±6.4x〖10〗^3, respectively.
Incidence of mold in examined vanilla, chocolate, mango, strawberry ice creams and frozen yoghurt samples as following; Alternaria Alternaria (33.3, 31.57, 31.8, 93.3 and 47.4%); Aspergillus Niger (20, 15.79, 13.6, 16.7 and 0%), Aspergillus flavus (20, 15.79, 9.1, 12.5 and 0%), Aspergillus ochraceus (0, 0, 4.5, 4.2 and 15.9%), Aspergillus parasiticus (0, 0, 4.5, 4.2 and 0%), Cladosporium spp. (6.67, 0, 9.1, 0 and 0%), Mucor (6.67, 10.52, 0, 0 and 10.5%), Penicillium (13.3, 26.32, 27.2, 29.1 and 26.3), respectively.
The current investigation has indicated a poor overall level of hygiene in the service of different flavors of examined ice creams and frozen yoghurt in Alexandria governorate.
The safety and quality of different flavors ice creams and frozen yoghurt samples sold at Alexandria city were investigated. Samples were collected randomly from different shops, supermarkets and street vendors in Alexandria governorate. Egypt from February 2017 to June 2017.
7.1. Chemical evaluation of examined frozen dairy dessert:
7.1.1. Determination of the fat content
Mean value for fat content were (8.19±0.81), (8.91±1.27), (14.28±2.05), (4.29±1.26) and (11.67±3.04) in examined vanilla, chocolate, mango, strawberry ice creams and frozen yoghurt samples, respectively.
7.1.2. Determination of the solid not fat content:
Mean value of solids not fat content were (36.55±2.54), (41.99±5.28), (40.58±6.34), (19.50±2.57) and (34.10±3.49) in examined vanilla, chocolate, mango, strawberry ice creams and frozen yoghurt samples, respectively.
7.1.3. Determination of protein content:
Mean value of protein content in examined vanilla, chocolate, mango, strawberry ice cream samples and frozen yoghurt were (13.76±.97),(15.63±1.84),(15.15±2.31),(7.63±.92) and (12.77±1.34),repectively.
7.1.4. Determination of lactose content
Mean value of lactose content in examined vanilla, chocolate, mango, strawberry ice creams and frozen yoghurt samples were (19.74±1.36), (23.21±2.93), (22.33±3.57), (11.17±1.33) and (17.76±2.13); respectively.
7.2. Sanitary evaluation by grading of examined frozen dairy dessert samples:
7.2.1. Methylene Blue Reduction Test (MBRT)
MBRT ice cream samples over 4 hours (Grad 1): 15(75%), 10(50%), 7(35%) and 2(10%) of examined of vanilla, chocolate, mango and strawberry ice cream samples were Grade (1), respectively.
MBRT ice cream samples grad 2: 2(10%), 1(5%), 0(0%) and 1(5%) of examined vanilla, chocolate, mango and strawberry ice creams; respectively were Grade (2) with a good quality.
MBRT ice cream samples grad 3: 2(10%), 2(10%), 6(30%) and 2(10%) of examined vanilla, chocolate, mango and strawberry ice creams, respectively were Grade (3) with poor quality.
MBRT for ice cream samples grad 4(reduction time less than 30 minutes): 1(5%), 7(35%), 7 (35%) and 15(75%) of examined vanilla, chocolate, mango and strawberry ice creams; respectively which were Grade (4) with a bad quality.
MBRT for frozen yoghurt: 17(85%) of examined of frozen yoghurt samples showed Grade (4); 3(15%) showed grade (3).
7.3. Microbiological evaluation of the examined frozen dairy dessert samples:
7.3.1. Aerobic Mesophilic Plate Count (cfu/g):
Mean values of aerobic mesophilic plate count were 1.5x〖10〗^5±6.1x〖10〗^4, 9.5x〖10〗^6± 6.4x〖10〗^5, 4.8x〖10〗^6±2.4x〖10〗^6, and 5.1x〖10〗^7±1.8x〖10〗^7, of examined vanilla, chocolate, Mango and strawberry ice cream samples, respectively.
7.3.2. Coliforms count(cfu/g):
Mean values of Coliforms count of examined vanilla, chocolate, mango, strawberry ice creams and frozen yoghurt samples were 2.5x〖10〗^2±7.1x10, 6.6〖x10〗^2±2.5x〖10〗^2, 9.9x〖10〗^3±6.3x〖10〗^3, 4x〖10〗^3±1.4x〖10〗^3 and 1.5x〖10〗^2 ± 2.9x10, respectively.
Frequency distribution of isolated Coliforms from examined flavored ice cream with vanilla, chocolate, mango and strawberry were Citrobacter diverses (16.67, 20, 15 and 10%), Citrobacter freundii (8.33, 13.33, 5 and 10%), Enterobacter cloaca (25, 20,15 and 25%), Enterobacter aerogenes (8.33, 13.33, 15 and 10%), Enterobacter agglumerans (8.33, 13.33, 5 and 5%), Escherichia coli (0, 6.67, 10 and 15%), Klebsiella spp. (25, 6.67, 30 and 15%) and Serratia liquifaciens (8.33, 6.67, 5 and 10%), respectively.
Frequency distribution of isolated Coliforms in examined frozen yoghurt samples were; Citrobacter diverses, Citrobacter freundii, Enterobacter cloaca, Enterobacter aerogenes, Enterobacter agglumerans, Escherichia coli, Klebsiella spp. and Serratia liquifaciens in frozen yoghurt samples were (12.50, 6.25, 18.75, 12.50, 12.50, 6.25, 25 and 6.25%), respectively.
Serodaignosis of isolated E. coli from positive samples of examined frozen dairy desserts were 2(22.22%) O111: H2 (Enterohaemorrhagic E coli), 1(11.11%) O127: H6 (Enterotoxigenic E coli), 2(22.22%) O26:H11 (Enterohaemorrhagic E. coli), 1(11.11%) O55: H7 (Enteropathogenic E coli) and 1(11.11%) O91: H21 (Enterohaemorrhagic E coli); while there were 2 (22.22%) could not be identified.
Incidence of virulence gene of enteropathenic E.coli using multiplex PCR showed that 2 strains (100%) samples of E. coli O26 : H11 were Positive E. coli strains for Stx1, Stx2 and eaeA; 1 strain of E. coli O55 : H7 was positive for Stx2 gene only; 1 strain of E. coli O91 : H21 was Positive for Stx1 and Stx2 genes; 2 strains of E. coli O111 : H2 was Positive for Stx1, Stx2 and eaeA genes, while the other strain was Positive only for Stx1 and Stx2 genes, Finally 1 strain of E. coli O127 : H6 was Positive for Stx1gene.
7.3.3. Staphylococcus aureus Count (cfu/g):
Mean values of Staphylococcus aureus count in examined vanilla, chocolate, mango, strawberry ice creams and frozen yoghurt were 1.6x〖10〗^2±7.0x10, 3.4x〖10〗^2±9.4 x10, 1.9x〖10〗^3±1.5x〖10〗^3, 7.4x〖10〗^2±2.9x〖10〗^2, and 3.33x〖10〗^2±1.2x〖10〗^2(cfu/g), respectively.
7.3.4. Total mold count and identification of the isolated mold strains:
Mean values of mold count (cfu/g) in the examined vanilla, chocolate, mango, strawberry ice creams and frozen yoghurt samples were 2.2x〖10〗^2±8.4x10, 9.6x〖10〗^2±4.4x〖10〗^2, 3.2x〖10〗^3±1.3x〖10〗^3, 3.7x〖10〗^3±1x〖10〗^3 and 1.3x〖10〗^4±6.4x〖10〗^3, respectively.
Incidence of mold in examined vanilla, chocolate, mango, strawberry ice creams and frozen yoghurt samples as following; Alternaria Alternaria (33.3, 31.57, 31.8, 93.3 and 47.4%); Aspergillus Niger (20, 15.79, 13.6, 16.7 and 0%), Aspergillus flavus (20, 15.79, 9.1, 12.5 and 0%), Aspergillus ochraceus (0, 0, 4.5, 4.2 and 15.9%), Aspergillus parasiticus (0, 0, 4.5, 4.2 and 0%), Cladosporium spp. (6.67, 0, 9.1, 0 and 0%), Mucor (6.67, 10.52, 0, 0 and 10.5%), Penicillium (13.3, 26.32, 27.2, 29.1 and 26.3), respectively.
The current investigation has indicated a poor overall level of hygiene in the service of different flavors of examined ice creams and frozen yoghurt in Alexandria governorate.