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Abstract
One hundred and twenty three random samples, 68 of processed cheese, 30 processed cheese paste and 25 processed cheese blocks were collected from different localities in Alexandria Governorate for sensory, chemical and microbiological examinations.
7.1. Organoleptic quality: Sensory evaluation:
All samples were examined for flavour, body and texture and colour and appearance and it was found that
7.1.1. Processed cheese:
The total averages of organoleptic scores for processed cheese were 82.3, 90.75, 98.2, 66.4, 48.5and 88.5 for brand 1, 2, 3, 4, 5 and 6, respectively. Brand 3 scored the highest and brand 5 scored the lowest.
7.1.2. Processed cheese spread:
The total averages of organoleptic scores for processed cheese spread were79.3, 95.5 and 93.7 for brand 1, 2 and3, respectively. Brand 2 scored the highest and brand 1 scored the lowest.
7.1.3. Processed cheese blocks:
The total averages of organoleptic scores for processed cheese block were79 and 70.5 for brand A and B, respectively.
7.2. Compositional quality:
7.2.1. Processed cheese:
The mean values of sodium chloride %, titratable acidity %, fat% ,moisture %, dry matter%, fat/ dry matter% and ash % for examined processed cheese samples were1.78 ± 0.03 for brand 5 to 5.12 ± 0.01 for brand 2, 0.82 ± 0.05 for brand 6 and 3.15 ± 0.04 for brand 5, 23.36 ± 0.24 for brand 1 to 27.60 ± 0.92 for brand 5, 50.17 ± 1.73 for brand 5 to 54.65 ± 0.38 for brand1, 45.35 ± 0.38 for brand 1 to 49.83 ± 1.73a- for brand 5 , 50.30 ± 0.30 for brand 4 to 55.42 ± 0.46 for brand 5 and5.53 ± 0.05 for brand 5 to 7.82 ± 0.05 for brand 2 , respectively.
All the samples of brands 1, 3, 4 and 5 of examined processed cheese samples were complying with the Standards for salt content while all samples of brands 2 and 6 were not complying with the Standards.
All the samples of brands 1, 2 and 3 were complying with the Standards for moisture while 2(15.38%), 3 (30%) and 4(40%) of brands 4, 5 and 6 were out of this specification.
It was found that 14(100%), 7(70%) and 7(70%) examined samples of brand 2, 3 and 6 of processed cheese, respectively were not complying with the Standards for FDM%. While 3(23.08%) and 5(50%) of brand 4and 5 were not complying with the Standards for FDM%.
All the examined samples of the 6 brands of processed cheese spreads were complying with the Standards for Ash% which stated that ash must be around 8%.
7.2.2. Processed cheese paste (spread):
The mean values of sodium chloride %, titratable acidity %, fat% ,moisture %, dry matter%, fat/ dry matter% and ash % for brand 1 , 2 and 3 examined processed cheese paste samples were 4.39 ± 0.01, 5.11 ± 0.01 and 5.69 ± 0.01 / 0.33 ± 0.01, 0.32 ± 0.02 and 0.33 ± 0.07/ 27.40 ± 0.54, 23.00 ± 2.35 and 19.30 ± 2.61 / 54.80 ± 0.77, 60.05 ± 2.00 and 58.35 ± 2.08 / 45.20 ± 0.77 , 39.95 ± 2.00 and 41.65 ± 2.08 / 60.62 ± 0.61, 56.35 ± 4.49 and 44.68 ± 5.13 and 5.99 ± 0.23, 5.96 ± 0.26 and 7.29 ±0.38, respectively.
All the samples of the 3 brands of processed cheese paste were above the Egyptian Standards (1988) for salt content.
It was found that 3(30%), 7(70%) and 9(90%) of examined samples of brand 1, 2 and 3, respectively were not complying with the Standards for moisture.
It was found that 2(20%), 6(60%) and 9(90%) of examined samples of brand1, 2and3 of processed cheese spread were not complying with the Standards for FDM%.
All the examined samples of the 3 brands of processed cheese spreads were complying with the Standards for Ash% which stated that ash must be around 8%.
7.2.3. Processed cheese blocks:
The mean values of sodium chloride %, titratable acidity %, fat% ,moisture %, dry matter%, fat/ dry matter% and ash % were for examined processed cheese blocks samples of brand A and B were 4.82 ± 0.01 and 5.70 ± 0.01/ 0.84 ± 0.03 and 0.58 ± 0.06 / 19.23 ± 0.39 and 16.33 ± 0.47 / 58.01±0.90 and 59.81 ±1.03 / 41.99 ± 0.90 and 40.19 ± 1.03 / 45.81 ± 0.20 a and 40.62 ± 0.30 and 6.42 ± 0.12 and 5.35 ± 0.02, respectively.
All the examined samples of brand A and B (of processed cheese block) were out of the accepted limit for Sodium Chloride percent according to Egyptian standards (1988).
It was found that 2 (15.38%) and 11(91.66%) of examined samples of brand A and B, respectively were not complying with the Standards for moisture.
It was found that while1 (7.69%) and 3 (25%) of brand A and B of processed cheese block were not complying the Standards for FDM%.
All the examined samples of the 2 brands of processed cheese block (with plant oil) were complying with the Standards for Ash%.
7.3. Microbiological evaluation:
7.3.1. Processed cheese:
The mean values of total bacterial count, total psychrotrophs, total moulds counts and Staphylococcus aureus for processed cheese samples were ranged from 2.88 x10 to ± 0.30 x10 for brand 4 to 6.86 x 102 ± 2.32 x 102 for brand 3, 4 x 10 ± 1 x 10 for brand 6 to 3.59 x 104 ± 2.87 x 104 for brand5, 7.10 x 10 ± 2.82 x 10 for brand 2 to 8.52 x 103 ± 7.22 x 103 for brand 3, and no colony zero for brand 1 to 5.95 x 103 ± 4.85 x 103 for brand 4 cfu/g, respectively.
Coliforms failed to be detected in the examined processed cheese samples of the six brands except for one sample (10%) of brand 5 and its count was 6 x 102 cfu/g. The positive sample is out of E.S. Specification.
All samples of brand 1, 2, 3 and 4 of processed cheese free from for Enterococci. Enterococci were present in 2 samples (20%) and 2 samples (20%) of the examined samples of brand 5and 6, respectively.
All samples of the six brands of processed cheese were negative for stormy fermentation test, thus all the samples were complied with E.S. (2005a).
Staphylococcus aureus were detected in (0) 0 %,( 1) 7.14%, (4) 40%, (8) 61.5%, (8) 80% and (1) 10% of processed cheese samples of brand 1, 2,3,4,5 and 6, respectively. The positive samples are out of E.S. Specification.
Aerobes were detected in (6) 54.54 %,( 7) 50%, (10) 100%, (10) 76.92%, (8) 80%and (3) 30% of processed cheese samples of brand 1, 2,3,4,5 and 6, respectively.
Psychrotrophs were detected in (2) 18.18 %,( 9) 64.28%, (4) 40%, (10) 76.92%, (5) 50%and (2) 20% of processed cheese samples of brand 1, 2,3,4,5 and 6, respectively.
Yeasts were negative in the 6 brands while moulds were detected in (9) 81.81 %,( 10) 71.42 % 4 (4) 40%, (4) 30.77%, (7) 70% and (9) 90% of processed cheese samples of brand 1, 2,3,4,5 and 6, respectively. The positive samples are out of ES Specification.
The frequency distribution of isolated mould species from examined processed cheese samples were Aspergillus flavus 6 (13.96%), Aspergillus Niger 9(20.93%), Aspergillus fumigatus13 (30.23%), Alternaria alternaria 4 (9.3%), Absidia 2 (4.65%), Penicillium 5 (11.63%), Rhizomucor 2 (4.65%) and Mucor 2 (4.65%).
The frequency distribution of isolated Coliform species from examined processed cheese samples were 1 (20%) was E.coli, 2 (40%) were Klebsiella , 1 isolate (20%)was Enterobacter cloacae and 1 (20%)was Enterobacter liquefaciens.
The frequency distribution of isolated Enterococci species from examined processed cheese samples were5 (62.5%) were Enterococcus faecalis and 3 (37.5%) were Enterococcus faecium.
The frequency distribution of isolated staphylocccai species from examined processed cheese samples were17 (54.84%) were Staphylococcus aureus coagulase +ve, 9 (29.03%) were Staphylococcus aureus coagulase -ve and 5 (16.12%) were Staphylococcus epidermis.
7.3.2. Processed cheese paste (spread):
The mean values of total bacterial count, total psychrotrophs, total yeasts and total moulds counts and Staphylococcus aureus for processed cheese spread samples for brand 1, 2 and 3 were 0, 1 x 10 and 3 x 104/0, 0 and 1.11 x 103 ± 1.10 x 103/3 x 10 ± 2 x 10, 1 x 10 ± 0.00 and 1.83 x 102 ± 1.56 x 102 /0, 0 and 1.05 x 102 ± 9.5 x 10, respectively.
All samples of spread cheese of all brands were negative for Enterococci.
All samples of spread cheese of all brands were negative for Coliforms.
All samples of spread cheese of all brands were negative for stormy fermentation test.
Aerobes were detected % (0)0 %,( 1) 10% and (1) 10% in of processed cheese spread samples of brand 1, 2and 3, respectively.
Psychrotrophs were detected % (0)0 %,( 0) 0% and (2) 20% in of processed cheese spread samples of brand 1, 2and 3, respectively.
Moulds were detected % (4)40 %,( 5) 50% and (4) 40% in of processed cheese spread samples of brand 1, 2and 3, respectively.
Staphylococci were detected % (0)0 %,( 0) 0% and (2) 20% in of processed cheese spread samples of brand 1, 2and 3, respectively.
The frequency distribution of isolated mould species from examined processed cheese spread samples were Aspergillus flavus 3(42.86%), Aspergillus Niger 1(14.29%), Alternaria alternaria 1(14.29%) and Penicillium 2 (28.57%).
The frequency distribution of isolated Staphylococcal species from examined processed cheese spread samples were 3 (75%) were 4 isolates (57.14%) were Staphylococcus aureus coagulase +ve, 2 isolates (28.57%) were Staphylococcus aureus coagulase -ve and 1 isolate (14.29%) was Staphylococcus epidermis.
7.3.3. Processed cheese blocks:
The mean values of total psychrotrophs for processed cheese block samples for brand A and B were 2.20 x 103 and 1.28 x 103 ± 6.25 x 102, respectively.
The mean values of and total moulds counts for processed cheese block samples for brand A and B were 1 x 10 and 1.67 x 10 ± 0.33 x 10,respectively.
All samples of all brands were negative for total aerobic bacteria.
All samples of all brands were negative for Enterococci.
All samples of all brands were negative for coliforms. All processed cheese block samples comply with the E.S. for Coliforms.
All samples of the two brands were negative for Staphylococcus aureus except for one sample of brand 8 was positive for staphylococci (8.33%; with count of 3 x 102 cfu/g).
All samples of the two brands were negative for Stormy fermentation test except for 2samples (15.38%) of brand 7 and 2samples of brand 8 were (16.67%) positive for Stormy fermentation test.
The frequency distribution of isolated moulds species from examined processed cheese block samples were Aspergillus flavus 4 (23.53%), Aspergillus Niger 7(41.18%), Aspergillus fumigatus 2(11.76%),Penicillium 2(11.76%), Rhizomucor 1 (5.88%) and Mucor 1(5.88%).
The frequency distribution of isolated Staphylococci species from examined processed cheese block samples were3 isolates (75%) were Staphylococcus aureus coagulase +ve and 1 isolates (25%) were Staphylococcus aureus coagulase –ve.
The frequency distribution of isolated Clostridia species from examined processed cheese block samples were 2 (33.33%) were Clostridium sporogenes, 1 (16.67%) was Clostridium perfringens and 3 (50%) were Clostridium butyrcium.
The significance and public health importance of the isolated organisms were discussed and the suggestive control measures for improving the criteria and sanitary conditions of 3 types of processed cheese were discussed.