Peptides in the 3-kDa ultrafiltrate of fermented whey protein isolate (WPI) medium could be responsible for the antivirulence activity of Lactobacillus helveticus LH-2 and Lactobacillus acidophilus La-5 against Salmonella Typhimurium. Non-fermented and fermented media containing 5.6% WPI were fractionated at a 3 kDa cut-off and the filtrate was analyzed by mass spectrometry. The non-fermented WPI medium contained 109 milk derived peptides, which originated from β-casein (52), αs1-casein (22), αs2-casein (10), κ-casein (8), and β-lactoglobulin (17). Most of these peptides were not found in the fermented media, except for 14 peptides from β-casein and one peptide from αs2-casein. Database searches confirmed that 39 out of the 109 peptides had established physiological functions, including angiotensin-converting-enzyme (ACE) inhibitory, antioxidant, antimicrobial, or immunomodulating activity. A total of 75 peptides were found in the LH-2 cell free spent medium (CFSM): 54 from β-casein, 14 from k-casein, 4 from β-lactoglobulin and 3 from αs2-casein. From these peptides, 19 have previously been associated with several categories of bioactivity. For La-5 CFSM, a total of 15 peptides were sequenced: 8 from β-casein, 5 from αs1-casein, 2 from β-lactoglobulin. Only 5 of these have previously been reported as having bioactivity. Many of the peptides remaining in the fermented medium would contain low-affinity residues for oligopeptide binding proteins and higher resistance to peptidase hydrolysis. These properties of the sequenced peptides could explain their accumulation after fermentation despite the active proteolytic enzymes of LH-2 and La-5 strains. Down-regulated expression of hilA and ssrB genes in S. Typhimurium was observed in the presence of La-5 and LH-2 CFSM. Downregulation was not observed for the Salmonella oppA mutant strain exposed to the same CFSM used to treat the S. Typhimurium DT104 wild-type strain. This result suggests the importance of peptide transport by S. Typhimurium for down regulation of virulence genes in Salmonella.

This study was conducted to evaluate the quality of raw cow milk at the farm level which considered the first step for production of safe and high quality milk. A total of 150 raw cow milk samples were collected from governmental and private farms at Alexandria Governorate, Egypt. The samples were analyzed for bacteriological properties. The mean values of TBC, coliforms ,Staphylococcus aureus and Aeromonas hydrophila count in positive samples were 3.22 × 10 4 ± 7.28 × 10 3 , 1.4 × 10 3 ± 3.9 × 10 2 , 5.26 ×10 2 ± 8.1 × 10 and 6.4 ×10 ± 1.3 × 10 in examined raw cow milk collected from governmental farms while the respective counts in raw cow milk collected from private farms were 1.51 × 10 5 ± 2.59 × 10 4 , 3.28 × 10 2 ± 4.7 × 10, 2.95 × 10 2 ± 7.7 × 10 and 6.8 ×10 ± 4.1 × 10. Also prevalence of some pathogens as E. coli ,Salmonellae and Yersinia enterocolitica organisms were detected .The hygienic as well as the public health significance of raw milk were discussed.

The assessment of sanitary measures of Ras cheese was undertaken through microbiological evaluation of cheese and its processing environments in traditional manufacturing dairy plant in Alexandria Governorate. A total of 215 representative samples include received raw milk (25), cheese curd (25), fresh Ras cheese (25), three months aged Ras cheese (25), and six months aged Ras cheese (25), As well as swabs from cheese vat (15), stainless-steel cylindrical forms (15), stainless-steel tables (15) and hand workers (15) were taken. Also (15) samples of rennet and (15) samples of annatto (coloring agent) were collected. The trials were repeated 3 times from 3 different patches within 6 months to ensure the most contaminated points. Raw milk was heavily contaminated as the mean values of total bacterial count , coliform count , S. aureus count and total mold & yeast count were 1.11 x 10 7 ± 2.45 x 10 6 cfu/ml , 8.24x10 4 ± 1.68x10 4 cfu/ml , 7.77 x10 2 ± 4.33x10 2 cfu/ml and 4.10x10 2 ± 2.0x10 2 cfu/ml, respectively .Meanwhile slight decline of all these counts was observed in curd samples. Then the counts increases again in fresh cheese samples specially Coliforms and S. aureus counts as follow 1.88 x10 3 ± 8.13 x10 cfu/gm and 1.64x10 3 ± 3.66 x10 2 cfu/gm, respectively. Three aged cheese samples revealed slight reduction in Coliforms and S. aureus counts as follow 1.44 x10 2 ± 2.14 x10 cfu/gm and 8.41x10 ± 1.80x10 cfu/gm, respectively. Meanwhile, 6 months aged cheese samples showed great reduction of Coliforms and S. aureus counts as follow 0.2 x10 ± 0 cfu/gm and 2.66 x10 ±8.43x10 cfu/gm respectively indicating the fact that the prolonged aging of Ras cheese increases the safety of the product. Samples of rennet, Cheese vat, stainless-steel cylindrical forms and stainless-steel tables showed high contamination with TBC and Coliforms while hand workers swabs were harbored high S. aureus and Coliforms counts. Results posed that the most reliable sources of contamination along Ras cheese manufacturing line were received raw milk, rennet, vats, forms, tables as well as hand workers. Preventive measures and GMP these could be applied to improve the hygienic quality of Ras cheese were fully discussed.

Key words:pasteurized milk, cheese, Coliforms, Staphy. aureus, EnterococciThis study was planned to indicate that how the health authorities realize the importance of frequent inspection of milk and dairy products to check whether; these meet the minimum legal standard to offer in a safety state to hospitals patients, but also on the freedom from microorganisms and its hazards. A total of Two hundred and fifty random samples of pasteurized milk, Damietta cheese, Kareish cheese, Ras cheese and yoghurt (50 of each) were collected randomly in clean, dry and sterile containers, from food Department in Alexandria hospitals. 90% of examined samples were complied with Egyptian standards which stated that thermoduric count of pasteurized milk must <30000/ml. All examined samples of Damietta, Kareish and Ras cheeses have different counts of total bacterial count. The incidence of Enterococci counts in the examined Damietta, Kareish, Ras cheeses and yoghurt samples were 54, 82, 66, and 48, respectively. Egyptian standards stated that Coliforms count of pasteurized milk and cheeses must not exceed <10/ml or g. the present study revealed that the percent of examined pasteurized milk, Damietta, Kareish, Ras cheeses and yoghurt samples that comply with that Standards were 62, 10, 6, 6 and 38%, respectively. While, the incidence of Staphylococcus aureus in the examined pasteurized milk, Damietta, Kareish, Ras cheeses and yoghurt samples were 30, 24, 66, 56 and 30%, respectively. These results emphasize the need for applying stricter hygienic practices, efficient heat treatment, and applying HACCP and GHP systems.

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