A total of 50 samples of balady and automatically packaged plain yoghurt (25 of each) were collected
from different dairy shops, groceries and supermarkets at Kalubia Governorates. The collected samples
were transferred immediately to the laboratory in an ice box for detection of Staph.aureus,its
enterotoxins produced and detection of virulent genes responsible for enterotoxins production. The
obtained results revealed that, Staph. aureus could be detected in three samples (12%) and two samples
(8%) of examined balady and automatically packaged plain yoghurt, respectively. Isolated strains were
tested for detection of enterotoxins producing genes by using PCR. The obtained results showed that
one strain belonged to each of balady and automatically packaged plain yoghurt proved to have gene
type (A) and (D), respectively. Also detection of enterotoxins by using ELISA revealed that one strain
of both balady and automatically packaged plain yoghurt was enterotoxigenic, types (A) and (D)
production at percentage of (33.33% and 50%), respectively. The public health importance and hygienic
significance of the isolated Staph. aureus and their entertoxins as well as the suggested measures for
improving the quality and safety of the yoghurt was discussed