Comparative studies on the microbial load of flavoured and unflavoured drinking yoghurt

Abstract EN

To assess the accuracy and helpfulness of plain and flavored drinking yoghurt, one hundred and fifty random samples (thirty each) of plain, strawberry, mango, banana and orange were collected from different supermarkets in Cairo and Giza Governorates, Egypt.

The examined samples were analyzed to assess and compare the microbiological quality of plain and flavored drinking yoghurt samples before their expiry or sell-by date.

The data obtained revealed that, aerobic spore former count were determined in different types of examined plain, strawberry, mango, banana and orange samples with a mean values of 6.4×103 ± 1.1×102, 1.3 × 105 ± 2.1 × 104, 3.2 × 106±4.3 × 105, 6.9 × 105±7.2 × 104 and 4.2 × 106 ± 6.6 × 105, respectively.

Mold and yeast counts were detected in 30, 100, 100, 100 and 90 % of the examined samples.

Coliforms, Enterococci and, Staphylococci were detected in different kinds of examined flavored drinking yoghurt.

Pseudomonas and Aero Monas as well as Bacillus cereus were present in the examined samples with percentages ranged from 23.3 to 66.7 % and 0 to 36.6%, respectively.

Salmonella and Yersinia were not detected in all examined samples.

The survival of Listeria monocytogenes in drinking yoghurt stored at refrigerator for 30 days was investigated.

The public health significance and economic importance of different microbial groups as well as recommended hygienic measures were discussed.