Evaluation of some fermented milks sold in Alexandria City

Abstract EN

One hundred and twenty random samples of some locally manufactured fermented dairy products including; plain yoghurt, stirred yoghurt, flavored yoghurt, baladi rayeb, sterilized rayeb and Labnah (20 each) were collected from local markets in Alexandria city to be examined for their sanitary and microbiological evaluation.

The obtained results clarified that the mean value of the titratable acidity was 0.83±0.007, 0.65±0.01, 0.68±0.011, 0.89±0.005, 0.66±0.01 and 0.14±0.08 %, respectively.

In addition, the mean value of coliforms count cfu/g was 4.10×102 ± 20; <10; 1.72×102 ± 21; 1.65×103 ± 2.69×102 ; <10 and 6.10×10 2 ± 64, respectively.

The isolated coliforms species were Citrobacter freundii, E.coli, Enterobacter aerogenes, Enterobacter cloacae, Proteus vulgaris, Edwardsiella tarda and Klebsiella pneumoniae.

None of them was isolated from stirred yoghurt and sterilized rayeb.

The mean value of Staph.

aureus count cfu/g was 22 ±5; 20± 10; 64± 45; 7.23×102 ± 54; 2.1×102 ± 21 and 95± 12, respectively.

The mean value of Enterococci count cfu/g was 1.25×102 ± 12; 1.25×102 ± 23.2; 1.21×102 ± 11; 4.25×102 ± 1.97×102 ; 22.5± 13 and 1.66×103 ± 6.6×102 , respectively.

Moreover, the yeasts and molds counts were performed.

The mean value of yeasts count cfu/g was 7.87x104 ± 6.89x104 ; 5.83x103 ± 3.68x103 ; 2.16x103 ± 6.54x102 ; 1.26x104 ± 3.55x103 ; 9.11x103 ± 3.82x103 and 1.28x103 ± 0.79x 102 , respectively.

While the mean value of molds count cfu/g was 5.88x104 ± 4.06x104 ; 2.60x103 ±1.12x103 ; 7.57x103 ± 4.72x103 ; 2.92x103 ± 4.38x102 ; 3.00x103 ± 1.41x103 and 2.75x103 ± 1.12x103 , respectively.

It could be concluded that the majority of the investigated fermented dairy products were contaminated, at different degrees, with coliforms, Staph.

aureus, yeasts and molds giving an indication of poor sanitary measures adopted during manufacturing, storage, handling and distribution of these products.

In addition, it was observed that baladi rayeb and Labnah had lower quality than the other examined fermented dairy products.