Isolation of enterotoxigenic harboring gene and enteropathogenic (serogroups O18, O114, and O125) from soft and hard artisanal cheeses in Egypt.

BACKGROUND

Soft and hard artisanal cheeses are regularly consumed in Egypt. These products are usually processed from raw milk which may harbor many pathogenic and spoilage microorganisms.

AIM

To evaluate the safety of some artisanal cheeses in Egypt, such as Ras, Domiati, and Mish, through chemical and microbiological examination.

METHODS

One hundred and fifty random samples of traditional Ras, Domiati, and Mish cheeses (50 each) were microbiologically and chemically analyzed. Counts of total bacteria, presumptive coliform, staphylococci, yeast, and mold were estimated. Furthermore, isolation of was performed, followed by PCR confirmation; isolates of were examined for the presence of virulence genes; on the other hand, the detection of the five classical enterotoxin genes of was performed using multiplex PCR. Regarding chemical analysis, moisture, salt, and acidity content were measured. Correlations between chemical and microbial findings were investigated.

RESULTS

Mean counts of total bacteria, presumptive coliform, staphylococci, yeast, and mold were (2 × 10, 3 × 10 and 1 × 10 ), (3 × 10, 5 × 10 and 5 × 10), (1 × 10, 4 × 10and 1 × 10), (3 × 10, 1 × 10 and 5 × 10), and (7 × 10, 4 × 10 and 3 × 10) for Ras, Domiati and Mish cheeses, respectively. Serological identification of suspected revealed that O125 was isolated from Ras and Domiati samples, O18 was recovered from Ras samples, while O114 was isolated from Mish samples. PCR results revealed that all detected isolates of were positive for both iss (increased serum survival) and fimH (type 1 fimbriae) genes. Concerning isolated , all examined products were harboring enterotoxigenic strains, with and genes being the most common. The mean values of moisture, salt, and acidity were (30.03, 56.44, and 58.70), (3.30, 6.63, and 7.56) and (0.65, 0.68, and 0.50) for Ras, Domiati, and Mish cheeses, respectively.

CONCLUSION

Enterotoxigenic harboring gene and enteropathogenic (serogroups O18, O114, and O125) were frequently isolated from soft and hard artisanal cheeses in Egypt. Therefore, strict hygienic measures should be applied during their manufacture, handing, and distribution.