Non O157:H7 Shiga-toxin- Producing Escherichia coli (STEC) is a major foodborne pathogen that cau... more Non O157:H7 Shiga-toxin- Producing Escherichia coli (STEC) is a major foodborne pathogen that causes severe disease in humans ranged from mild gastroenteritis to critical illness and death. This study investigated survival of (STEC) during storage of experimentally manufactured kareish cheese. Cheese were prepared using pasteurized milk inoculated with 2 STEC strains (O26& O111) at (9 log10 CFU/g) with and without yogurt starter culture (Lactobacillus. bulgaricus and Streptococcus. thermophilus) & 3% NaCl, then expulsion of whey and stored at refrigerator. The obtained results revealed that mean STEC counts (log10 CFU/g) were 6.46±5.66 , 6.06 ± 5.75 at zero time then reached 8.01±7.69, 8.07 ± 7.76 ( their maximum count) on 12 th day of storage, finally decreased to 4.63±4.55, 4.34 ± 4.08(at 21th day) in (O26&O111) treated groups with starter culture. Concerning (O26&O111) un treated groups, the mean STEC counts were 6.67±5.32, 6.50±5.98 at zero time then reached to 9.08±8.65, 9.11±8.90 on 12 th day, finally decreased to5.53±4.85, 5.61±4.82 at 15 th day of storage at refrigerator. Effect of starter culture on survival of STEC were highly significant (P< 0.05).In conclusion presence of starter culture in manufactured Karish cheese significantly enhanced reduction of Non O157:H7 STEC counts over its storage time.
Background: Lactoferrin is a natural biological active cationic protein that can be used as a yog... more Background: Lactoferrin is a natural biological active cationic protein that can be used as a yogurt additive to inhibit the growth of foodborne pathogens. Objectives: The present study evaluated the antimicrobial effects of lactoferrin against Bacillus cereus, Enterococcus faecalis, and Candida albicans inoculated in laboratory prepared yogurt at refrigerator temperature. Methods: The pre-warmed skimmed milk was inoculated by commercial starter and then divided into 3 parts, each inoculated by different inoculum and a certain concentration of lactoferrin (0.5% and 1.5%) and incubated at 42oC for 4 h till curd formation. Tenfold serial dilutions were performed for each group and refrigerated at4±1oC for up to 14 days to be examined every day. Results: The obtained results showed that the treated yogurt samples with lactoferrin had significant reductions in B. cereus, Ent. faecalis, and C. albicans counts than untreated samples (control positive). Generally, yogurt samples treated wi...
The contamination of milk and its dairy products with different microorganisms could cause public... more The contamination of milk and its dairy products with different microorganisms could cause public health hazards. Antibacterial nanoparticles (NPs) are a novel way to ensure that milk and milk products are safe. The present study investigated the effect of chitosan NPs (CS-NPs) and selenium NPs (Se-NPs) on some microorganisms, which consequently affect raw milk and Kareish cheese. Small-sized nanomaterials of Se-NPs and CS-NPs at the size of approximately 20 nm were used in this study. The samples were 700 ml raw milk and 700g Kareish cheese manufactured from 3000 mg milk. The concentrations of used nanoparticles were 0.5%, 1%, and 1.5% for Se-NPs and 2.5%, 5%, and 10% for CS-NPs. They were used to improve the microbial properties of milk and Kareish cheese samples during storage at the refrigerated temperature of 4°C. The aerobic plate count, Enterobacteriaceae count, Staphylococcus count, and mold count were significantly reduced in milk and Kareish cheese samples treated with CS-...
Purpose: The current study’s aim is to investigate the effect of hydrolyzed whey protein concentr... more Purpose: The current study’s aim is to investigate the effect of hydrolyzed whey protein concentrate (WPC) derived from camel’s milk on growth of some fungi inoculated in soft cheese during refrigerated storage. Methodology: The pepsin-trypsin (P-T) camel´s WPC hydrolysate (20 mg/g) was incorborated in to soft cheese and their effects on the survival of Candida albicans, Asperigillus fumigatus Asperigillus flavus and Asperigillus niger (103-104cfu/g) were examined till cheese deterioration. Findings: The results revealed that P-T hydrolysate had the ability to decrease the viability of C.albicans, A.fumigatus A.flavus and A.niger in soft cheese. C.albicans was the most sensitive strain. Unique contribution to theory, practice and policy: Thus, camel´s WPC hydrolysates can be exploited as. This study was conducted to elaborate antifungals from camel´s WPC after enzymatic hydrolysis which could serve as a safe alternative of...
Recently, probiotics and their extracted bacteriocin are used in food preservation especially in ... more Recently, probiotics and their extracted bacteriocin are used in food preservation especially in fermented foods as drinking yoghurt. Lactobacillus gasseri (Lb. gasseri) is widely recognized as one of the important porbiotics and has potential healthy role in suppressing the growth of some spoilage and pathogenic bacteria by its bactriocin. Bacteriocin of Lb. gasseri was extracted and its antibacterial activity was detected against (Bacillus subtiles, Staph. aureus and E.coli) by agar diffusion assay. Lb. gasseri and its extracted bacteriocin were inoculated separately in the examined drinking yoghurt samples. All groups were examined for T.A%, microbiological examination and sensory evaluation at time of production and weekly till signs of spoilage were detected. Obtained results revealed that the drinking yoghurt group samples which contain Lb. gassri bacteriocin showed the lowest T.A% and highly significant inhibitory effect on the examined pathogenic and spoilage microorganisms ...
Non O157:H7 Shiga-toxin- Producing Escherichia coli (STEC) is a major foodborne pathogen that cau... more Non O157:H7 Shiga-toxin- Producing Escherichia coli (STEC) is a major foodborne pathogen that causes severe disease in humans ranged from mild gastroenteritis to critical illness and death. This study investigated survival of (STEC) during storage of experimentally manufactured kareish cheese. Cheese were prepared using pasteurized milk inoculated with 2 STEC strains (O26& O111) at (9 log10 CFU/g) with and without yogurt starter culture (Lactobacillus. bulgaricus and Streptococcus. thermophilus) & 3% NaCl, then expulsion of whey and stored at refrigerator. The obtained results revealed that mean STEC counts (log10 CFU/g) were 6.46±5.66 , 6.06 ± 5.75 at zero time then reached 8.01±7.69, 8.07 ± 7.76 ( their maximum count) on 12 th day of storage, finally decreased to 4.63±4.55, 4.34 ± 4.08(at 21th day) in (O26&O111) treated groups with starter culture. Concerning (O26&O111) un treated groups, the mean STEC counts were 6.67±5.32, 6.50±5.98 at zero time then reached to 9.08±8.65, 9.11±8.90 on 12 th day, finally decreased to5.53±4.85, 5.61±4.82 at 15 th day of storage at refrigerator. Effect of starter culture on survival of STEC were highly significant (P< 0.05).In conclusion presence of starter culture in manufactured Karish cheese significantly enhanced reduction of Non O157:H7 STEC counts over its storage time.
Background: Lactoferrin is a natural biological active cationic protein that can be used as a yog... more Background: Lactoferrin is a natural biological active cationic protein that can be used as a yogurt additive to inhibit the growth of foodborne pathogens. Objectives: The present study evaluated the antimicrobial effects of lactoferrin against Bacillus cereus, Enterococcus faecalis, and Candida albicans inoculated in laboratory prepared yogurt at refrigerator temperature. Methods: The pre-warmed skimmed milk was inoculated by commercial starter and then divided into 3 parts, each inoculated by different inoculum and a certain concentration of lactoferrin (0.5% and 1.5%) and incubated at 42oC for 4 h till curd formation. Tenfold serial dilutions were performed for each group and refrigerated at4±1oC for up to 14 days to be examined every day. Results: The obtained results showed that the treated yogurt samples with lactoferrin had significant reductions in B. cereus, Ent. faecalis, and C. albicans counts than untreated samples (control positive). Generally, yogurt samples treated wi...
The contamination of milk and its dairy products with different microorganisms could cause public... more The contamination of milk and its dairy products with different microorganisms could cause public health hazards. Antibacterial nanoparticles (NPs) are a novel way to ensure that milk and milk products are safe. The present study investigated the effect of chitosan NPs (CS-NPs) and selenium NPs (Se-NPs) on some microorganisms, which consequently affect raw milk and Kareish cheese. Small-sized nanomaterials of Se-NPs and CS-NPs at the size of approximately 20 nm were used in this study. The samples were 700 ml raw milk and 700g Kareish cheese manufactured from 3000 mg milk. The concentrations of used nanoparticles were 0.5%, 1%, and 1.5% for Se-NPs and 2.5%, 5%, and 10% for CS-NPs. They were used to improve the microbial properties of milk and Kareish cheese samples during storage at the refrigerated temperature of 4°C. The aerobic plate count, Enterobacteriaceae count, Staphylococcus count, and mold count were significantly reduced in milk and Kareish cheese samples treated with CS-...
Purpose: The current study’s aim is to investigate the effect of hydrolyzed whey protein concentr... more Purpose: The current study’s aim is to investigate the effect of hydrolyzed whey protein concentrate (WPC) derived from camel’s milk on growth of some fungi inoculated in soft cheese during refrigerated storage. Methodology: The pepsin-trypsin (P-T) camel´s WPC hydrolysate (20 mg/g) was incorborated in to soft cheese and their effects on the survival of Candida albicans, Asperigillus fumigatus Asperigillus flavus and Asperigillus niger (103-104cfu/g) were examined till cheese deterioration. Findings: The results revealed that P-T hydrolysate had the ability to decrease the viability of C.albicans, A.fumigatus A.flavus and A.niger in soft cheese. C.albicans was the most sensitive strain. Unique contribution to theory, practice and policy: Thus, camel´s WPC hydrolysates can be exploited as. This study was conducted to elaborate antifungals from camel´s WPC after enzymatic hydrolysis which could serve as a safe alternative of...
Recently, probiotics and their extracted bacteriocin are used in food preservation especially in ... more Recently, probiotics and their extracted bacteriocin are used in food preservation especially in fermented foods as drinking yoghurt. Lactobacillus gasseri (Lb. gasseri) is widely recognized as one of the important porbiotics and has potential healthy role in suppressing the growth of some spoilage and pathogenic bacteria by its bactriocin. Bacteriocin of Lb. gasseri was extracted and its antibacterial activity was detected against (Bacillus subtiles, Staph. aureus and E.coli) by agar diffusion assay. Lb. gasseri and its extracted bacteriocin were inoculated separately in the examined drinking yoghurt samples. All groups were examined for T.A%, microbiological examination and sensory evaluation at time of production and weekly till signs of spoilage were detected. Obtained results revealed that the drinking yoghurt group samples which contain Lb. gassri bacteriocin showed the lowest T.A% and highly significant inhibitory effect on the examined pathogenic and spoilage microorganisms ...
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Papers by Hend A. Elbarbary