الفهرس 
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Abstract
A total of 120 random samples of processed cheese, Domiati cheese, powdered milk, UHT milk , pasteurized milk and raw milk (20 of each) were purchased from different groceries and supermarkets in Giza Governorate-Egypt. These samples were subjected to mycological examination for isolation and identification of different Fungal species as well as total mould and yeast colony count, also subjected to RT-PCR. The overall incidence rate of the moulds in processed cheese, Domiati cheese, powder milk, UHT milk, pasteurized milk and raw milk were 90%, 30%, 35%,0%,30% and 80%,respectively .
The predominant isolated genera in processed cheese were Aspergillus spp. with incidence of 36 (62%), followed by Penicillium spp. 10(17.2%) while Eupenicillium spp. 6(10.3%), Fusarium spp. 4(7%) and Phoma spp.2(3.5%). The predominant mould genera isolated in Domiati cheese were Aspergillus spp. with incidence of 10 (83.3%), followed by Penicillium spp. 2 (16.7%). The predominant genera in powdered milk were Aspergillus spp. 4 (50%) while Penicillium spp. and Alternaria spp were 2(25%). UHT milk were free from any mould genera while in pasteurized milk the predominant genera were Aspergillus spp. 2 (33.3%), also Penicillium spp. and Epicoceum spp. were 2(33.3%). The predominant genera in raw milk were Penicillium spp. 16 (44.5%), Aspergillus spp. 14 (38.9%) and Geotrichum spp. 6 (16.6%)
A. flavus was the most isolated Aspergillus spp.; it was presented as(66.7%), (40%), (100%) and ( 42.8%) in processed cheese , Domiati cheese ,Powdered milk and raw milk, respectively but not detected in UHT and pasteurized milk. Followed by A.niger(16.7%), (100%)and (28.6%) in processed cheese ,pasteurized and raw milk, respectively. Also A.flocculosus(5.6%), A.versicolor(5.5%)and A.sydowii(5.5%) detected in processed cheese.AlsoA.fumigatus(20%) and A.ustus(40%) were detected in Domiati cheese While A.terreus (28.6%) detected in raw milk but in UHT milk samples not detected any Asperigellus Spp..
The most predominant penicillium species isolated from processed cheese were P.aethiopicum, p.cammberti, p.citreonigrum, P.implicatium and P.simplicissimum with an equale incidence of 2 (20%). While P.aurantiogriseum were 2 (100%) in Domiati cheese and 6 (37.5%) in raw milk. P.citreonigrum were 2 (100%) in pasteurized milk and P.reqforti were 2 (100%) in powdered milk .Also in raw milk P.crustosum were 6 (37.5%), P.digitatum and P.oxalicumwere in equal incidence of 2 (12.5%) . There is no any penicillium spp. in UHT milk. The most predominant other species isolated from processed cheese were Eupenicillium ochrasalmoneum4(33.2%) ,while Eupenicillium hirayramae ,Fusarium chlamedosporum, Fusarium semitectum and Phoma sorghina were detected in the same incidence of 2(16.7%). Alternaria alternate 2(100%) detected in powdered milk. Also Epicoceum nigrum 2(100%) detected in pasteurized milk and Geotrichum candidum 6(100)detected in raw milk. .
An incidence of yeasts in Domiati cheese and raw milk samples are 50% and 80% ,respectively. While there is no detection to any yeast spp. in processed cheese, powder milk ,UHT milk and pasteurized milk samples. The most predominant yeast species isolated from Domiati cheese were Debaryomyces hansenii 14 (53.8%),Pichia anomala 8 (30.8%), Pichiamembranafaciens 2 (7.7%) and Sacharomyces cervisioe 2 (7.7%). While C.tropicalis, C.pseudotropicalis, Sacharomyces cervisioe and Torulopsis in the equal incidence of 2 (14.3%)were detected in raw milk. Also Rhodotorula 6 (42.8%) detected in raw milk.
Different types of milk products samples(20 processed cheese , 20 Domiati cheese,20 powdered milk, 20UHT milk , 20 pasteurized milk and 20 raw milk) were examined for presence of aflatoxin M1 by Fluorometer under the ideal experimental condition.AFM1 not detected in processed cheese. AFM1 detected in 4 (20) samples of Domiati cheese represent (20%)and the minimum level was 3 ppb and the maximum was 11 ppb with a mean value of 6.2±1.8μg /Kgm . AFM1 detected in 3 (20) samples of powder milk represent (15%) and the minimum level was 0.52 ppb and the maximum was 0.9 ppb with a mean value of 0.73±0.11μg /Kgm .Also AFM1 detected in 2 (20) samples of UHT milk represent (10%) and the minimum level was 0.61 ppb and the maximum was 0.78 ppb. AFM1 detected in 4 (20) samples of pasteurized milk represent (20%) and the minimum level was 0.44 ppb and the maximum was 1.0ppb with a mean value of 0.59±0.14μg /L whileAFM1 detected in 3( 20) samples of raw milk represent (15%) and the minimum level was 0.66 ppb and the maximum was 0.69 ppb with a mean value of 0.67±0.01μg/L.
In this study some milk and dairy samples , negative on the culture so 9(2 from each type except the processed cheese , 1from raw milk) of them were subjected to ITS SYBR green RT-PCR, six of them were positive (2 Domiati chees,1 powdered milk,1raw milk,2 pasteurized milk ) with RT-PCR, this result indicates presence of fungi in those six samples. There are two possibilities to those positive samples, either they contain dead cells so didn’t grow on the culture or may be viable but non culturable cells(VBNC).To distinguish between dead cells and VBNC cells, 6 +ve samples in RT- PCR are subjected to pre-treatment with nucleic acid intercalating dyes, such as propidium monoazide (PMA), prior to RT- PCR .As a result all of the six positive samples in RT-PCR was positive after PMA treatment and this indicates that all positive samples in RT-PCR containing VBNC fungi. In conclusion , these results revealed that the ordinary mycological examination not efficient to identification of some types of fungi especially which contain viable but non culturable cells(VBNC)in milk and dairy products. So the methods of RT-PCR with PMA treatment are the most efficient methods for these fungiidentification.