Abstract
Egyptian Ras cheese (Roumy cheese) is a popular cheese due to its affordable price and considered as one of the most harmful cheeses for human health, and we are not even referring to its high content of saturated fats and not to its high salt content but to the contamination with different types of mycobiota and its harmful toxins. The purpose of this study is to enumerate, isolate and identify mycobiota contaminating such cheeses. In addition, determination of mycotoxin residues in the examined Ras cheese samples and compare their incidence in the surface (Rind) and core in the examined cheese samples after cutting 2.5 cm from the rind. Therefore, One hundred Ras cheese samples were collected from supermarkets, small diaries, groceries in Alexandria governorate, Egypt. The obtained results revealed that the examined Ras cheese samples were contaminated with yeast with a mean count of 7.5× 106 ± 1.1× 106 cfu/g and 5.8× 10⁴± 1.04× 10⁴ cfu/g for surface and core with an incidence of 54% and 70%, respectively. While, the incidence of mould contamination were 59% and 56% with a mean count of 4.9 × 105 ± 0.83 × 105 cfu/g and 6.33 × 10³ ± 1.9 × 10³ cfu/g for surface and core, respectively. Aflatoxins M1, M2, B1, B2, G1, G2 and Ochratoxin A were detected in the surface of examined pooled Ras cheese samples with an incidence rate of 41.66, 25, 33.3, 25, 16.6, 8.3 and 16.6%, respectively. Core of examined pooled Ras cheese samples were also contaminated with the mentioned aflatoxins types except AFM2 and AFG2 were not detected while the determined mycotoxins types were AFM1, AFB1, AB2, AG1 with an incidence of 16.6, 33.3, 16.6 and16.6%, respectively. Ochratoxin A has been detected only in group number 9 of pooled Ras cheese samples with and incidence of 8.33%. By all accounts, and with proven results; it is obvious that the majority of collected ras cheese samples were contaminated with a wide range of mycobiota and their secondary metabolic toxins “mycotoxins”. Strict hygienic measures should be applied to plants of cheese production in order to reduce the risk of mould growth and mycotoxins release.

Key words: Ras cheese, Yeast, Moulds, Mycotoxins.