الفهرس Only 14 pages are availabe for public view
 |  | from | 134 |  |  |
| | | from | 134 | | |
Abstract
A total of 180 random samples of raw milk and milk products including Kareish cheese, Domiati cheese, processed cheese, ice cream and yoghurt (30 samples each) were collected from dairy shops, street vendors and supermarkets in Assiut City.
The samples were examined for the occurrence of coliforms, faecal coliforms, E. coli, Enterococci, anaerobes and Cl. perfringens and for detection the relationship between the E. coli, Enterococci and Cl. perfringens as faecal contaminants.
This investigation revealed that all of the examined raw milk and Kareish cheese samples were contaminated with coliforms and the majority of the positive samples (90 and 76.7%) each had count ranged from 103-<104 cfu/ml or g, respectively. However, the incidences of coliforms in Domiati cheese, processed cheese, ice cream and yoghurt samples were 23.3, 16.7, 93.3 and 46.7%, respectively.
Concerning the incidence of coliforms, 96.7, 13.3, 10, 86.7 and 46.7 of Kareish, Domiati, processed cheese, ice cream and yoghurt samples, respectively were unacceptable according to the permissible levels of Egyptian Standards.
The percentages of faecal coliforms in examined raw milk, Kareish cheese, Domiati cheese, processed cheese, ice cream and yoghurt samples were 60, 83.3, 6.7, 6.7, 56.7 and 36.7%, respectively.
In case of E. coli, it was declared that only one sample (3.3%) from each raw milk, Domiati cheese and processed cheese was contaminated with this pathogen in count <10, <102 and <10 cfu/ ml or g, respectively. However, it was isolated from 33.3, 6.7 and 20% of Kareish cheese, ice cream and yoghurt samples, respectively.
It is apparent from the obtained results that, 66.7, 96.7, 96.7, 93.3 and 80% of Kareish, Domiati, processed cheese, ice cream and yoghurt samples, respectively were in order with the permissible limits of Egyptian Standards.
Enterococci could be detected in 83.3% of the examined raw milk samples in count ranged from <102 to 2.1x106 with an average value of 1.2x105 cfu/ml. The highest frequency distribution (32%) lied in the range of 104-<105 cfu/ml.
83.3% of Kareish cheese samples contained Enterococci in count ranged from <102 to 6.7x106 cfu/g with an average count of 1.5x106. The highest frequency distribution (44%) had count within the range of 106-<107 cfu/g.
In case of Domiati cheese, 26.7% of samples proved to be contaminated with Enterococci and the count ranged from <102 to 7.4x105 cfu/g with an average count of 4.1x104 cfu/g. 25% of the positive samples were equally distributed among the counts of <102 cfu/g and 104-<105 cfu/g. 20, 70 and 40% of processed cheese, ice cream and yoghurt contained this microorganism in counts ranged from <102 to 3.8x104, <102 to 7.0x106 and <102 to 9.3x105 cfu/ml or g, respectively. The average value of these samples were 1.4x103, 3.7x105 and 4.7x104 cfu/ml or g, respectively.
The main isolated Enterococci strains from the evaluated samples were Ent. faecalis, Ent. faecium, Ent. hirae, Ent. durans, Ent. dispare, Ent. mundtii, Ent. saccharolyticus, Ent. cecorum and Ent. columbae in various percentages and Ent. faecalis and Ent. faecium were the most predominant strains.
Regarding anaerobes, 73.3, 83.3, 43.3, 13.3, 73.3 and 33.3% of the examined samples, respectively were contaminated with anaerobes.
Cl. perfringens could be detected in 3.3% of the examined Kareish cheese samples, while it failed to be detected in all of the examined raw milk, Domiati cheese, processed cheese, ice cream and yoghurt samples. So, all samples of raw milk and milk products were satisfactory and in accordance to the Guidelines for the microbiology of some ready to eat food samples at the point of sale.
It was evident that, there was a significance correlation between the incidences and counts of E. coli and Enterococci in Domiati cheese samples, while no evidence of correlation was found between the incidence and count of E. coli, Enterococci and Cl. perfringens in each of raw milk, Kareish cheese, processed cheese, ice cream and yoghurt samples.
The suggestive hygienic control measure for improving the quality of milk and milk products was discussed.