الفهرس 
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Abstract
The present work studied “Assessment of hygienic status of egg by products sold at local markets”. Therefore, Ninety samples of mayonnaise and twenty-five samples of salad dressing were collected randomly from supermarkets and restaurants at local market in El-Behera, kafr El-sheikh and Alexandria Governorates for chemical and microbiological evaluation.
The obtained results could be summarized in the following items.
1. Keeping quality evaluation of mayonnaise and salad dressing.
The mean value of pH value in examined mayonnaise samples was 3.81± 0.16, while in examined salad dressing was 4.76 ± 0.13.
The mean value of acid value in examined mayonnaise samples was 6.23± 2.03, while in examined salad dressing was 3.12± 0.91.
2. Spoilage markers for evaluation of mayonnaise and salad dressing
The mean value of thiobarbituric acid value in examined mayonnaise samples was 0.61±0.33 malonaldehyde (mg/kg), while in examined salad dressing was 0.44± 0.11 malonaldehyde (mg/kg).
The mean value of total volatile nitrogen in examined mayonnaise samples was 11.49± 7.34 mg/100 g, while in examined salad dressing was 7.19±2.62 mg/100 g.
3. Microbiological evaluation of mayonnaise and salad dressing.
Aerobic bacterial count was detected in 91.11% of mayonnaise samples ranged from 1.0x103 to 9.90x104 with a mean value of 3.05x104± 2.47x104 cfu/g, while aerobic mesophilic count was detected in 40% of examined salad dressing, ranged from 2.0x104 to1.3x105 with a mean value of 6.98x104± 4.52 x104 cfu/g.
Egyptian Standards (2007) stated that aerobic bacterial count in mayonnaise should be not more than103 cells/g, there were 8.89% of examined mayonnaise samples were compatible and 91.11% were incompatible with these standards, while in salad dressing all examined samples were incompatible.
Enterococci were detected in 17.77 and 20% of examined mayonnaise and salad dressing with mean values of 2.93x103± 1.56x103 and 5.2x103± 3.19x103 cfu/g, respectively.
Staphylococcus aureus was detected in 75.55% of examined mayonnaise samples ranged from 1.0x102 to 7.4x103 with a mean value of 1.16x103± 1.0x103 cfu/g, while was detected in 40% of examined salad dressing, ranged from 9.0x102 to 8.1x103 with a mean value of 3.68x103± 2.94x103 cfu/g.
Egyptian Standards (2007) stated that mayonnaise and salad dressing should be free from Staphylococcus aureus, there were 24.45% of examined mayonnaise samples were compatible and 75.56% were incompatible with these standards, while in salad dressing samples 60% were compatible and 40% were incompatible with these standards.
Yeast were detected in 38.88 and 20% of examined mayonnaise and salad dressing samples with mean values of 2.8x102± 2.18x102 and 1.4x102± 5.47x102 cfu/g, respectively.
Egyptian Standards (2007) stated that yeast cells in mayonnaise and salad dressing should be not more than 20 cells/g, there were 61.11% of examined mayonnaise samples were compatible and 38.89% were incompatible with these standard, while in salad dressing samples 80% were compatible and 20% were incompatible with these standards.
Moulds were detected in 88.8 and 40% of examined mayonnaise and salad dressing samples and ranged from (1.0x102 to 4.8x103) and (6.0x102 to 3.0x103) with a mean value of 1.08x103± 1.0 x103 and 1.73 x103± 8.38 x102 cfu/g, respectively.
Egyptian Standards (2366/2007) stated that mould count in mayonnaise and salad dressing should be not more than 20 cells/g, there were 11.11% of examined mayonnaise samples were compatible and 88.89% were incompatible with these standards, while in salad dressing 60% were compatible and 40% were incompatible with these standards.
Salmonellae failed to be detected in the examined mayonnaise and salad dressing samples. Egyptian standards (2366/2007) stated that mayonnaise and salad dressing must be free from Salmonella species, therefore all examined mayonnaise and salad dressing samples were compatible with these standards.