Production of three anti-listerial peptides by Lactobacillus curvatus in MRS broth.

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

Enhancing The Antilisterial Effect Of Lactobacillus Curvatus Cwbi-B28 In Pork Meat And Cocultures By Limiting Bacteriocin Degradation

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 ▲]

Detection of bacteriocin genes in Enterococcus strains isolated from peruvian traditional cheese, artisanally-produced.

Poster (2007, June)

Inhibitory activity of lactobacillus curvatus CWBI-B28 against Listeria monocytogenes and ST2-verotoxin producing Escherichia coli O157

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 ▲]

Antilisterial 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

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

Industrial application of an antilisterial strain of Lactobacillus curvatus THT 0030550 as a protective culture : effect of fat and curing agent sodium nitrite on the production and the activity of bacteriocin.

Poster (2004, December 17)

Biocontrol of listeria monocytogenes in smoked salmon by in situ bacteriocin production from Lactobacillus curvatus and Lactobacillus lactis ssp. Lactis

Poster (2003, August)

Biocontrol Of Listeria Monocytogenes In A Model Cultured Milk (Lben) By In Situ Bacteriocin Production From Lactococcus Lactis Ssp Lactis

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 ▲]