Cheese is one of the most popular dairy products in Egypt. It supplies the body with protein, fat, vitamins and minerals.
Cheese may be exposed to bacterial contamination during manufacture, distribution and/or storage. This study was
undertaken to investigate the bacteriological status of different cheese types marketed in Zagazig city, Egypt. The obtained
results showed that Roumy cheese had the highest total mesophilic and psychrophilic counts followed by white, soft and
cheddar cheese types. Furthermore, the coliforms count and prevalence of different serotypes of E. coli in cheese samples
were detected. In addition, the expression of shiga-toxin producing genes (stx1 & stx2) in the identified E. coli serotypes
was screened using multiplex PCR. The obtained results revealed that only E. coli O₁₂₇:H₆ had expressed both stx1 & stx2
toxin producing genes, while E. coli O₁₁₁:H₄ had expressed only stx1 gene, however, both E. coli O₁₂₄: H and O₅₅:H₇ had
expressed stx2 gene. The public health importance of shiga-toxin producing E. coli was detected