References of "Ghalfi, H"
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See detailCombined use of bacteriocin-producing strains to control Listeria monocytogenes regrowth in raw pork meat.
Kouakou, P.; Ghalfi, H.; Dortu, C. et al

in International Journal of Food Science & Technology (2010), 45

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See detailProduction of three anti-listerial peptides by Lactobacillus curvatus in MRS broth.
Ghalfi, H.; Benkerroum, N.; Ongena, Marc ULg et al

in Food Research International (2010), (43), 33-39

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See detailEffects of curing sodium nitrite additive and natural meat fat on growth control of Listeria monocytogenes by the bacteriocin-producing Lactobacillus curvatus strain CWBI-B28.
Kouakou, P.; Ghalfi, H.; Destain, Jacqueline ULg et al

in Food Microbiology (2009), 26

In realistic model meat systems, the separate and combined effects of fat content and sodium nitrite on the antilisterial activity of the bacteriocin of Lactobacillus curvatus CWBI-B28 were studied. In ... [more ▼]

In realistic model meat systems, the separate and combined effects of fat content and sodium nitrite on the antilisterial activity of the bacteriocin of Lactobacillus curvatus CWBI-B28 were studied. In laboratory fermentations where Listeria monocytogenes was co-cultured at 4 C with bacteriocin-producing CWBIB28 in lean pork meat (fat content: 13%) without added nitrite, a strong antilisterial effect was observed after one week. The effect was maintained for an additional week, after which a slight and very gradual rebound was observed. Both added nitrite (20 ppm) and a high-fat content (43%) were found to antagonise this antilisterial effect, the Listeria cfu count reached after six weeks being 200 times as high in high-fat meat with added nitrite than in lean meat without nitrite. This antagonism could not be attributed to slower growth of the bacteriocin-producing strain, since CWBI-B28 grew optimally in fatrich meat with 20 ppm sodium nitrite. Bacteriocin activity was also measured in the samples. The observed activity levels are discussed in relation to the degree of antilisterial protection conferred [less ▲]

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See detailComparison Of Yarrowia Lipolytica Lipase Immobilization Yield Of Entrapment, Adsorption, And Covalent Bond Techniques
Alloue, Wam.; Destain, Jacqueline ULg; El Mejdoub, Thami ULg et al

in Applied Biochemistry and Biotechnology (2008), 150(1),

The purpose of this study was to immobilize lipase from Yarrowia lipolytica using three methods including inclusion, adsorption, and covalent bond to study enzyme leaching, storage, and catalytic ... [more ▼]

The purpose of this study was to immobilize lipase from Yarrowia lipolytica using three methods including inclusion, adsorption, and covalent bond to study enzyme leaching, storage, and catalytic properties. Sodium alginate and chitosan were the polymers selected to immobilize lipase by inclusion. The beads of each polymer were dried by freeze drying and fluidization. The results show that chitosan was more adapted to the inclusion of lipase. Even though freeze dried, bead activity was low compared to that of fluidized beads. The freeze-drying process seems to produce suitable beads for storage at 4 and 20 °C. The immobilization by adsorption was carried out on both celite and silica gel. Maximum immobilization yield of 76% was obtained with celite followed by 43% in silica gel. The enzyme adsorbed on the two supports exhibited greater stability at a certain temperature (50 °C) and in no polar solvents (Isooctane, n-heptane, and n-hexane). In addition, the lipase immobilized by covalent bond retained residual activity equitable to 70%. It was demonstrated that the enzyme immobilized by covalent bond showed greater activity (80%) after 5 months of storage. [less ▲]

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See detailEnhancing The Antilisterial Effect Of Lactobacillus Curvatus Cwbi-B28 In Pork Meat And Cocultures By Limiting Bacteriocin Degradation
Kouakou, P.; Ghalfi, H.; Destain, Jacqueline ULg et al

in Meat Science (2008), 80(3),

This work focused on Listeria monocytogenes growth inhibition and growth rebound in raw and cooked pork meat inoculated with Lactobacillus curvatus strains. During storage of raw meat homogenates in the ... [more ▼]

This work focused on Listeria monocytogenes growth inhibition and growth rebound in raw and cooked pork meat inoculated with Lactobacillus curvatus strains. During storage of raw meat homogenates in the presence of the bacteriocin-producing strain Lactobacillus curvatus CWBI-B28wt, the Listeria monocytogenes cfu count was initially reduced to an undetectable level, but a growth rebound occurred after two weeks, coinciding with loss of 70% of the bacteriocin activity present at the end of week 2. The Listeria growth rebound was suppressed when proteolysis of bacteriocin was countered by the absence of proteases (bacteriocin addition to cooked meat) or the presence of 1% soy flour (added to provide competing substrates). Further experiments confirmed that bacteriocin is sensitive to the action of proteolytic enzymes isolated from both Lactobacillus curvatus CWBI-B28wt and the meat matrix. Bacteriocin proteolysis thus emerges as a cause of Listeria growth rebound. [less ▲]

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See detailImmobilisation de la lipase de Yarrowia lipolytica.
Alloue, W. A. M.; Destain, Jacqueline ULg; El Mejdoub, Thami ULg et al

Poster (2007, December)

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See detailEffectiveness of cell-adsorbed bacteriocin produced by Lactobacillus curvatus CWBI-B28 and selected essential oils to control Listeria monocytogenes in pork meat during cold storage.
Ghalfi, H.; Benkerroum, N.; Doguiet, D. D. K. et al

in Letters in applied microbiology (2007), 44(3),

Aims: To study the effectiveness of a combination of cell-adsorbed bacteriocin (CAB; a suspension of producer cells on which maximum bacteriocin has been immobilized by pH adjustments) of a Lactobacillus ... [more ▼]

Aims: To study the effectiveness of a combination of cell-adsorbed bacteriocin (CAB; a suspension of producer cells on which maximum bacteriocin has been immobilized by pH adjustments) of a Lactobacillus curvatus strain with oregano or savory essential oil to control Listeria monocytogenes in pork meat at 4 C. [less ▲]

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See detailInhibitory activity of lactobacillus curvatus CWBI-B28 against Listeria monocytogenes and ST2-verotoxin producing Escherichia coli O157
Ghalfi, H.; Thonart, Philippe ULg; Benkerroum, N.

in African Journal of Biotechnology (2006), 5(22), 2303-2306

A bacteriocin- producing strain of Lactobacillus curvatus CWBI- B28 isolated from raw meat was shown to inhibit Listeria monocytogenes and pathogenic strains of Escherichia coli by the well diffusion ... [more ▼]

A bacteriocin- producing strain of Lactobacillus curvatus CWBI- B28 isolated from raw meat was shown to inhibit Listeria monocytogenes and pathogenic strains of Escherichia coli by the well diffusion assay. To confirm whether the bacteriocin was involved in E. coli O157 inhibition, growth of the pathogen was monitored in the neutralized cell- free supernatant ( NCFS) pre- treated with pronase E or catalase. Alternatively, E. coli O157 ( VH21) was co- cultured with Lb. curvatus CWBI- B28 in MRS broth. The results of the well- diffusion assay suggested that the inhibition of E. coli O157 ( VH21) was partially due to the bacteriocin; however, growth monitoring indicated that such inhibition is exclusively due to hydrogen peroxide. In pronase- added NCFS ( i. e., absence of bacteriocin) the colony forming units ( cfus) of E. coli O157 ( VHA21) declined to below the detectable limit after 24 h of incubation at 37 C. However, in presence of catalase no inhibition of the pathogen was observed and the cfus increased steadily to reach 8 log units in 24 h. Moreover, in co- culture, a significantly accelerated inhibition of E. coli O157 ( VH21) was observed in MRS broth as compared to the NCFS without added catalase and the cfus decreased to below the detectable limit in 8 h instead of 24 h, respectively. [less ▲]

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See detailBacteriocin Activity By Lactobacillus Curvatus Cwbi-B28 To Inactivate Listeria Monocytogenes In Cold-Smoked Salmon During 4 Degrees C Storage
Ghalfi, H.; Allaoui, A.; Destain, Jacqueline ULg et al

in Journal of Food Protection (2006), 69(5),

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See detailAntilisterial Bacteriocin-Producing Strain Of Lactobacillus Curvatus Cwbi-B28 As A Preservative Culture In Bacon Meat And Influence Of Fat And Nitrites On Bacteriocins Production And Activity
Ghalfi, H.; Kouakou, P.; Duroy, M. et al

in Food Science and Technology International (2006), 12(4),

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See detailBiocontrol Of Listeria Monocytogenes In A Model Cultured Milk (Lben) By In Situ Bacteriocin Production From Lactococcus Lactis Ssp Lactis
Benkerroum, N.; Ghouati, Y.; Ghalfi, H. et al

in International Journal of Dairy Technology (2002), 55(3),

Bacteriocin-producing (Bac+) Lactococcus lactis ssp. lactis CCMM/IAV/BK1 isolated from traditional lben was used in the preparation of lben from pasteurized milk to assess its potential inhibitory ... [more ▼]

Bacteriocin-producing (Bac+) Lactococcus lactis ssp. lactis CCMM/IAV/BK1 isolated from traditional lben was used in the preparation of lben from pasteurized milk to assess its potential inhibitory activity against Listeria monocytogenes ATCC 7644. Production of bacteriocin (arbitrary units, AU) in MRS broth fortified with yeast extract (MRSY) in a fermentor under controlled and uncontrolled pH conditions was also investigated. This Bac+ strain yielded about 35 times more bacteriocin when the pH was maintained constant at 6.5 than under varying pH conditions. To test the effect of in situ bacteriocin production against L. monocytogenes, lben was made from cow's milk artificially contaminated with approximately 107 cfu/mL and fermented with a mixed mesophilic starter culture consisting of the lactococcal Bac+ organism and Lc. lactis ssp. lactis biovar diacetylactis 66, a diacetyl-producing strain, in a ratio of 1 : 1. Numbers of L. monocytogenes were monitored during fermentation and storage of lben at refrigeration temperature (c. 7°C) for up to 6 days. Performances of the Bac+ starter were compared to those of an isogenic Bac- derivative strain obtained from the Bac+ starter by curing with ethidium bromide. The results showed that the amount of L. monocytogenes decreased to below the detectable level in a 1-mL sample within 24 h of storage at 7°C in lben fermented with the Bac+ starter culture. On the contrary, L. monocytogenes survived for 6 days of storage at 7°C in lben made with the Bac- starter. The Bac+ wild strain of the starter studied could be adequately used to produce lben or similar indigenous fermented milks of improved hygienic quality on an industrial scale. Alternatively, it could be used as an adjunct in minimally processed products or in products obtained from raw milk to add a safety factor. [less ▲]

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