Anticancer properties and mechanism insights of α-hederin.

α-Hederin is a natural bioactive molecule very abundant in aromatic and medicinal plants (AMP). It was identified, characterized, and isolated using different extraction and characterization technologies, such as HPLC, LC-MS and NMR. Biological tests have revealed that this natural molecule possesses different biological properties, particularly anticancer activity. Indeed, this activity has been investigated against several cancers (e.g., esophageal, hepatic, breast, colon, colorectal, lung, ovarian, and gastric). The underlying mechanisms are varied and include induction of apoptosis and cell cycle arrest, reduction of ATP generation, as well as inhibition of autophagy, cell proliferation, invasion, and metastasis. In fact, these anticancer mechanisms are considered the most targeted for new chemotherapeutic agents' development. In the light of all these data, α-hederin could be a very interesting candidate as an anticancer drug for chemotherapy, as well as it could be used in combination with other molecules already validated or possibly investigated as an agent sensitizing tumor cells to chemotherapeutic treatments.

Mathematical modeling of Escherichia coli O157:H7 growth in carrot juice influenced by Thymbra capitata essential oil, heat treatment, and storage temperature.

The aim of this study was to develop a mathematical model describing the survival of Escherichia coli O157:H7 in carrot juice treated with Thymbra capitata essential oil combined with mild heat treatment and stored at different temperatures. The viable count method was used to investigate the effect of the treatment on bacterial survival, and the response surface methodology was used to develop a statistical model fitting the data. The results showed that the variance of bacterial growth is explained by storage temperature (37 %) and heat treatment (35 %), these are followed by Thymbra capitata essential oil (18 %) and their interaction (9 %). Positive multiplicative interaction was obtained for any pair of the studied treatments and cooperative effect synergy was observed over a large domain of these factors. A mathematical model was successfully developed to describe Escherichia coli O157:H7 response to the selected factors, within the study limits, and to estimate the risk of juice contamination and shelf-life. Based on our results, the use of Thymbra capitata essential oil combined with heat treatment may control Escherichia coli O157:H7 growth in carrot juice stored at low temperature.

Prevalence, typing and antimicrobial resistance of Salmonella isolates from commercial shellfish in the North coast of Morocco.

Salmonellosis is one of the most common foodborne illnesses in the world. The irrational use of antibiotics in medicine and in animal nutrition has greatly favored the emergence and spread of resistant strains of non-typhoid Salmonella. This study aims the determination of the prevalence of Salmonella in bivalve mollusks in Northern Morocco, as well as the molecular typing and antibiotic susceptibility testing of the strains isolated from positive samples. In total, 150 samples from shellfish composed of mussels (Mytilus galloprovincialis), clams (Callista chione and Ruditapes descussatus) and oysters (Magallana gigas). Isolated Salmonella were characterized by Molecular techniques PCR, MLST and MLVA, phylogenetically grouped by MLSA, and susceptibilities were determined for 30 antimicrobial drugs using microdilution method by the BD Phoenix Automated Microbiology System. Prevalence of Salmonella enterica subsp. enterica was 12.67%, grouped in four serovars identified as Chester, Hadar, Typhimurium and Kentucky. Five different MLST STs (sequence types) were detected, ST1954 being the most common, which was mostly found in Chester isolates. Forty-two percent of the isolates showed resistance to more than one antibiotic, especially trimethoprim, sulfa drugs, quinolones and ß-lactam. There was a marked change in the serovars and antimicrobial resistance profiles of the Salmonella isolates in this study compared to those in previous studies.

Prevalence and antimicrobial profiling of Campylobacter spp. isolated from meats, animal, and human feces in Northern of Morocco.

The present work was carried out to understand the occurrence and antimicrobial susceptibility of Campylobacter spp., in various samples in Northern of Morocco. For this purpose, a random sampling was undertaken from butcher shops, traditional markets, and slaughterhouse. First, the research of Campylobacter was performed according to the Moroccan standard NM ISO: 10272-1 (2008). Second, the isolates were identified by biochemical tests and real time PCR. After the biochemical and molecular identification of suspected colonies, a disk diffusion method was executed to determine the sensitivity of Campylobacter spp. against 18 antibiotics. The results showed a moderate prevalence of Campylobacter species (130/466) recovered mainly on the Campylobacter blood base agar, where C. coli (108/130) were more prevalent comparable to C. jejuni (22/130) in poultry and cattle meat, raw milk, cloacal and surface swabs, and stool of patient suffering from diarrhea. The findings supported also the sensitivity of multiplex qPCR to detect Campylobacter strains compared to Moroccan standard NM ISO: 10272-1 (2008). Among our isolates, C. jejuni were the most susceptible strain toward colistin, florfenicol, gentamicin, streptomycin, and erythromycin. Nonetheless, the presence of multidrug Campylobacter resistant strains was highly observed in C. jejuni isolated, particularly, from broiler chickens toward the antibiotic classes of cephalosporin, penicillin, monobactam, quinolone, fluoroquinolone, sulfamide, as well as tetracycline. This may be due to common use of these drugs in veterinary medicine and farms as growth factor, which limits the usefulness of these molecules. Hence, the study highlights the importance of resistance profile monitoring of these pathogens in Northern of Morocco, in order to develop appropriate control measures and to reduce the emergence of multidrug-resistant strains.

Molecular identification and antibiotic resistance of bacteriocinogenic lactic acid bacteria isolated from table olives.

In the present study, lactic acid bacteria were isolated from table olive in Morocco. Random Amplified Polymorphic DNA fingerprinting with (GTG)'(5) primer revealed a remarquable variability within isolates. According to the molecular identification, Enterococcus faecium was the most dominant species isolated with 32 strains (84.21%), followed by 4 strains of Weissella paramesenteroides (10.52%), 1 strain of Leuconostoc mesenteroides (2.63%) and Lactobacillus plantarum (2.63%). All of the strains that were identified showed occurrence of more than one bacteriocin-encoding gene. Based on the results obtained, L. plantarum 11 showed a mosaic of loci coding for nine bacteriocins (pln A, pln D, pln K, pln G, pln B, pln C, pln N, pln J, ent P). A phenotypic and genotypic antibiotic resistance was also examined. L. plantarum 11, L. mesenteroides 62, W. paramesenteroides 9 and W. paramesenteroides 36 as well as all the strains of E. faecium were susceptible to ampicillin, clindamycin and teicoplanin; however, isolates showed a resistance profile against tetracycline and erythromycin. Except E. faecium 114, E. faecium 130 and L. plantarum 11, no antibiotic resistance genes were detected in all of the strains, which might be due to resistances resulting from non-transferable or non-acquired resistance determinants (intrinsic mechanism).

Isolation of Microalgae from Mediterranean Seawater and Production of Lipids in the Cultivated Species.

Isolation and identification of novel microalgae strains with high lipid productivity is one of the most important research topics to have emerged recently. However, practical production processes will probably require the use of local strains adapted to commanding climatic conditions. The present manuscript describes the isolation of 96 microalgae strains from seawater located in Bay M'diq, Morocco. Four strains were identified using the 18S rDNA and morphological identification through microscopic examination. The biomass and lipid productivity were compared and showed good results for Nannochloris sp., (15.93 mg/L/day). The lipid content in the four species, namely Nannochloropsis gaditana, Nannochloris sp., Phaedactylum tricornutum and Tetraselmis suecica, was carried out by high performance liquid chromatography coupled to mass spectrometry (HPLC-MS )highlighting the identification of up to 77 compounds.

The Contribution of Carotenoids, Phenolic Compounds, and Flavonoids to the Antioxidative Properties of Marine Microalgae Isolated from Mediterranean Morocco.

This study aimed to investigate the potential of four sea water microalgae, isolated and cultivated at M'diq Bay in Morocco, as a new source of natural antioxidants. These microalgae belong to different classes, including Phaedactylium tricornitum (Bacillariophyceae), Nannochloropsis gaditana (Eustigmatophyceae), Nannochloris sp (Trebouxiophyceae), and Tetraselmis suecica (Chlorodendrophycea). The antioxidant properties were screened by the use of in vitro assays, namely 2,2-difenil-1-picrylhydrazyl, Ferric reducing antioxidant power, and Ferrous ions chelating activity, and compoundidentification was carried out in methanol and acetone extracts of both dried and fresh microalgae biomass by HPLC-PDA-MS analysis. Among the investigated microalgae, Phaedactylium tricornutum was the richest one regarding its carotenoid (especially all-E-fucoxanthin) and phenolic (especially protocatechuic acid) contents, as well as antioxidant activity (65.5%), followed by Nannochloris sp, Tetraselmis suicica, and Nannochloropsis gaditana, with antioxidant activity of 56.8%, 54.9%, and 51.1%, respectively.

Marinobacter maroccanus sp. nov., a moderately halophilic bacterium isolated from a saline soil.

During the taxonomic investigation of exopolymer-producing halophilic bacteria, a rod-shaped, motile, Gram-stain-negative, halophilic bacterium, designated strain N4T, was isolated from a saline soil located in northern Morocco. Optimal growth of the isolate was at 30-37 ºC and at pH 7.0-8.0, in the presence of 5-7 % (w/v) NaCl. Useful characteristics for the phenotypic differentiation of strain N4T from other Marinobacter species included α-chymotrypsin and α-glucosidase activities and the carbohydrate assimilation profile. The major fatty acids detected in strain N4T were C16:0 and C18:1ω9c and the predominant respiratory quinone was ubiquinone-9. Sequence analysis of the 16S rRNA gene indicated that strain N4T belonged to the genus Marinobacter and was closely related to the type strains of Marinobacter adhaerens (99.04 % similarity), Marinobacter salsuginis (98.97 %) and Marinobacter flavimaris (98.36 %). Phylogenetic analysis of the rpoD gene sequence also showed that the nearest neighbours of strain N4T were M. salsuginis (91.49 % similarity), M. adhaerens and M. flavimaris (90.63 %). Strain N4T showed 87.98 % average nucleotide identity with M. flavimaris and M. salsuginis, and 87.47 % with M. adhaerens. Regarding in-silico genome-to-genome distance, strain N4T showed DNA-DNA hybridization values of 33.30 % with M. adhaerens, 34.60 % with M. flavimaris and 34.70 % with M. salsuginis. The DNA G+C content of strain N4T was 57.3 mol%. Based on the results of phenotypic characterization, phylogenetic analysis and genome comparison, strain N4T represents a novel species of the genus Marinobacter, for which the name Marinobacter maroccanus sp. nov. is proposed. The type strain is N4T (=CECT 9525T=LMG 30466T).

Essential oils of Origanum compactum increase membrane permeability, disturb cell membrane integrity, and suppress quorum-sensing phenotype in bacteria.

The aim of this study was to investigate antibacterial activity of Origanum compactum essential oils collected at three phenological stages on Escherichia coli and Bacillus subtilis. The antibacterial activity was evaluated using the agar-well diffusion assay. The MIC and MBC values were determined using the micro-dilution assay. The investigation of the antibacterial action was carried out by the evaluation of the effect of O. compactum essential oils on the antibacterial kinetic growth, the integrity of cell membrane and permeability of the cell membrane. The anti-quorum sensing activity was tested by the inhibition of the biofilm formation. The findings of this study showed that O. compactum essential oil has potent antibacterial activities against E. coli and B. subtilis. The lowest inhibition value against B. subtilis was obtained with O. compactum essential oil at the post-flowering stage (MIC = MBC = 0.0312% (v/v)). The antibacterial mechanisms of O. compactum essential oils are related to the disturbing of the cell membrane integrity and the increasing of the membrane permeability, which leads to the leakage of genetic materials (DNA and RNA). Moreover, O. compactum essential oils inhibited the formation of the biofilms, a phenotype that has been known to be quorum sensing regulated.

Essential oils of Origanum compactum increase membrane permeability, disturb cell membrane integrity, and suppress quorum-sensing phenotype in bacteria / 药物分析学报

The aim of this study was to investigate antibacterial activity of Origanum compactum essential oils collected at three phenological stages on Escherichia coli and Bacillus subtilis. The antibacterial activity was evaluated using the agar-well diffusion assay. The MIC and MBC values were determined using the micro-dilution assay. The investigation of the antibacterial action was carried out by the evaluation of the effect of O. compactum essential oils on the antibacterial kinetic growth, the integrity of cell membrane and permeability of the cell membrane. The anti-quorum sensing activity was tested by the inhibition of the biofilm formation. The findings of this study showed that O. compactum essential oil has potent antibacterial activities against E. coli and B. subtilis. The lowest inhibition value against B. subtilis was obtained with O. compactum essential oil at the post-flowering stage (MIC = MBC = 0.0312％ (v/v)). The antibacterial mechanisms of O. compactum essential oils are related to the disturbing of the cell mem-brane integrity and the increasing of the membrane permeability, which leads to the leakage of genetic materials (DNA and RNA). Moreover, O. compactum essential oils inhibited the formation of the biofilms, a phenotype that has been known to be quorum sensing regulated.

Evaluation of Antimicrobial Activity of Four Organic Acids Used in Chicks Feed to Control Salmonella typhimurium: Suggestion of Amendment in the Search Standard.

Today, the general public has become increasingly aware of salmonellosis problems. Organic acids are known by their antimicrobial potential and commonly used for improving the quality of poultry feed. In this context, the present work evaluated the inhibitory effect of four organic acids, namely, acetic acid, citric acid, lactic acid, and tartaric acid, at different levels of contamination by Salmonella typhimurium. The neutralization of these organic acids in vitro and in the presence of one-day-old chick's organs was also investigated during the search for Salmonella serovars in birds as described in the Moroccan standard "NM 08.0.550." The effect of four organic acids on Salmonella typhimurium was tested in vitro and in the presence of chick's organs at different concentrations set of strain and organic acids tested. The MIC results demonstrated that tartaric acid, citric acid, and acetic acid inhibited Salmonella typhimurium at concentrations of 0.312%, 0.625%, and 0.512% for the three levels of strain: 10, 100, and 103 CFU/ml, respectively, while lactic acid and depending on the amount of the strain introduced acts differently: 0.078% for 10 CFU/ml and 0.156% for 100 and 103 CFU/ml. The concentration of 0.04M of Na2HPO4 solution has proved, in vitro, in caecums and organs of chicks (in presence of organic acids) that strain introduced, even at low concentrations, can be recovered. The use of additives has beneficial effects in Salmonella control program. However, the present results recommend the amendment of Salmonella research standard, taking into account the probable presence of organic acids in digestive content of one-day-old chicks.

Medicinal plant products targeting quorum sensing for combating bacterial infections.

Traditional treatment of infectious diseases is based on compounds that aim to kill or inhibit bacterial growth. The bacterial resistance against antibiotics is a serious issue for public health. Today, new therapeutic targets other than the bacterial wall were deciphered. Quorum sensing or bacterial pheromones are molecules called auto-inducer secreted by bacteria to regulate some functions such as antibiotic resistance and biofilms formation. This therapeutic target is well-studied worldwide, nevertheless the scientific data are not updated and only recent researches started to look into its potential as a target to fight against infectious diseases. A major concern with this approach is the frequently observed development of resistance to antimicrobial compounds. Therefore, this paper aims to provide a current overview of the quorum sensing system in bacteria by revealing their implication in biofilms formation and the development of antibiotic resistance, and an update on their importance as a potential target for natural substances.

Chemical composition of Mentha pulegium and Rosmarinus officinalis essential oils and their antileishmanial, antibacterial and antioxidant activities.

The aim of the study was the determination of the chemical composition of Mentha pulegium L. and Rosmarinus officinalis L. essential oils and the evaluation of their antileishmanial, antibacterial and antioxidant activities. Essential oils (EOs) were isolated using steam distillation and the chemical composition was determined using GC-MS analysis. The antibacterial activity was tested against ten pathogenic strains using the diffusion method, the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) by microtitration assay. The antioxidant activity was estimated by DPPH free radical scavenging ability and ferric-reducing power. The antileishmanial activity was tested against Leishmania major, Leishmania tropica and Leishmania infantum using MTT (3-(4.5-dimethylthiazol-2yl)-2.5-diphenyltetrazolium bromide) assay. The yield of essential oils (v/w %) M. puleguim and R. officinalis based on dry weight were 5.4 and 2.7% respectively. GC/MS analysis of R. officinalis essential oil (ROEO) revealed the presence of 29 components, mainly represented by oxygenated monoterpenes (63.743%) and hydrocarbons monoterpenes (21.231%). Mentha pulegium essential oil (MPEO) revealed 21 components, mainly represented by oxygenated monoterpenes (83.865%). The major components of ROEO were α-pinene (14.076), 1,8-Cineole (23.673) and camphor (18.743), while menthone (21.164) and pulegone (40.98) were the main major components of MPEO. M. pulegium and R. officinalis EOs showed a significant antioxidant activity compared with ascorbic acid and Trolox to the IC50 values of 58.27 ± 2.72 and 85.74 ± 7.57 µg/mL respectively revealed by reducing power assay. As for the antibacterial effect, the highest zone diameters were shown by the MPEO against Bacillus subtilis (30 ± 1.43 mm) and Proteus mirabilis (28 ± 1.32 mm). These values are significantly important compared with those of the commercialized antibiotic (Erythromycin and Chlorophenicol). The lowest MIC and MBC values were obtained with MPEO against S. aureus MBLA (MIC = MBC = 0.25% (v/v)). While, ROEO has exhibited a bactericidal effect against Listeria monocytogenes (MIC = MBC = 0.5% (v/v)), Bacillus subtilis (MIC = MBC = 1% (v/v)) and Escherichia coli (MIC = MBC = 1% (v/v)). For the antileishmanial effect, ROEO is the most active against L. major (IC50 = 1.2 ± 0.36 µg/mL. While, the MPEO has the most leishmanicidal effect against L. major (IC50 = 1.3 ± 0.45 µg/mL). These findings show that the EOs of M. pulegium and R. officinalis are good sources of bioactive molecules that could have potential applications in the food and pharmaceutical industries.

Prevalence, serotype distribution, and antimicrobial resistance of Salmonella isolated from food products in Morocco.

INTRODUCTION: Salmonellosis is one of the most common foodborne diseases worldwide. The irrational use of antibiotics in medicine and in animal feed has greatly promoted the emergence and spread of resistant strains of non-typhoidal Salmonella. METHODOLOGY: A total of 464 food products were collected in Tetouan from January 2010 to December 2012. The isolation and identification of Salmonella were performed according to Moroccan standard 08.0.116. All isolates were serotyped and were then tested for antibiotic resistance using the disk diffusion method. RESULTS: The microbiological analysis showed that 10.3% of food samples were contaminated with Salmonella. Eleven serotypes were identified: Kentucky 22.9% (11/48), Agona 16.7% (8/48), Reading 12.5% (6/48), Corvallis 8.3% (4/48), Saintpaul 8.3% (4/48), Typhimurium 6.2% (3/48), Montevideo 6.2% (3/48), Enteritidis 4.2% (2/48), and 2% (1/48) for each of Israel, Hadar, and Branderup. Drug susceptibility testing showed that 39.6% of Salmonella were resistant to at least one antibiotic and 60.4% were susceptible to all tested antibiotics. The highest percentage of resistance was found to the following antimicrobial agents: nalidixic acid (27.1%), sulfonamides (25%), amoxicillin (12.5%), amoxicillin/clavulanic acid 12.5%, trimethoprim (10.4%), cephalothin (4.2%), and chloramphenicol (2.1%). CONCLUSIONS: This study revealed a relatively high prevalence of Salmonella in food products in Tetouan and a large percentage of drug-resistant strains. Hygienic measures should be rigorously implemented, and monitoring resistance of Salmonella is required to reduce the risks related to the emergence of multi-resistant bacteria.

Characterization of haloglycan, an exopolysaccharide produced by Halomonas stenophila HK30.

We have conducted a thorough study of the exopolysaccharide (EPS) produced by strain HK30 of Halomonas stenophila, which we have named haloglycan. This strain was chosen during an ongoing research programme aimed at finding novel exopolysaccharide-producing halophilic bacteria in unexplored hypersaline habitats. Strain HK30 was isolated from a saline-wetland in Brikcha (Morocco) and identified as belonging to the species H. stenophila. It produced EPS mainly during the exponential growth phase and to a lesser extent during the stationary phase. Culture parameters influenced both bacterial growth and EPS production, EPS yield always being directly related to the quantity of biomass. Under optimum culture conditions, strain HK30 produced 3.89 g of EPS per litre of medium. The polymer was a sulphated heteropolysaccharide composed of two fractions, with molecular masses of 8.2 × 10(4) and 1.4 × 10(6). The crude EPS contained 44 ± 0.1% w/w carbohydrates and the following monosaccharide composition: glucose (24 ± 1.73), glucuronic acid (7.5 ± 0.37), mannose (5.5 ± 0.17), fucose (4.5 ± 0.36), galactose (1.2 ± 0.17) and rhamnose (1 ± 0.05) (%, w/w). It produced solutions of high viscosity and pseudoplastic behaviour that showed interesting flocculating and emulsifying activities and was also involved in forming biofilm.

Halomonas rifensis sp. nov., an exopolysaccharide-producing, halophilic bacterium isolated from a solar saltern.

A polyphasic taxonomic study was conducted on strain HK31(T), a moderately halophilic bacterium isolated from a solar saltern in Chefchaouen, Morocco. The strain was a Gram-reaction-negative, oxidase-positive rod, which was motile by means of peritrichous flagella. The strain required NaCl for growth and grew in salt concentrations (mixture of sea salts) of 0.5-20 % (w/v) (optimum 5-7.5 %, w/v), at 25-45 °C (optimum 32 °C) and at pH 5-10 (optimum pH 6-9). Strain HK31(T) did not produce acids from sugars and its metabolism was respiratory, using oxygen as terminal electron acceptor. The strain was positive for the accumulation of poly-ß-hydroxyalkanoate granules and formed mucoid colonies due to the excretion of an exopolysaccharide. The DNA G+C content was 61.5 mol%. 16S rRNA gene sequence analysis indicated that it belonged to the genus Halomonas in the class Gammaproteobacteria. The most phylogenetically related species was Halomonas anticariensis, with which strain HK31(T) showed a 16S rRNA gene sequence similarity of 96.48 %. Its major fatty acids were C(18 : 1)ω7c, C(16 : 0), C(19 : 0) cyclo ω8c, C(16 : 1)ω7c/iso-C(15 : 0) 2-OH and C(12 : 0) 3-OH and the predominant respiratory lipoquinone was ubiquinone with nine isoprene units (Q-9). Based on the evidence provided in this study, strain HK31(T) (= CECT 7698(T) = LMG 25695(T)) represents a novel species of the genus Halomonas, for which the name Halomonas rifensis is proposed.

Total phenolic content and antioxidant activity of myrtle (Myrtus communis) extracts.

The total phenolic content and antioxidant activity of methanolic, ethanolic and aqueous extracts of myrtle (Myrtus communis) leaves and berries were measured to find new potential sources of natural antioxidants. Total phenolic content was assessed by the Folin-Ciocalteau assay, while the antioxidant activity was evaluated by three methods: diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity assay, the reducing antioxidant power assay and beta-carotene linoleic acid assay. The total phenol content of myrtle extracts ranged between 9.0 and 35.6 mg GAE per g extract. For each solvent, leaf extracts contained significantly higher amount of total phenolic compounds than berry extracts. All of the extracts presented antioxidant capacity assessed by the three methods, but at different levels depending on the concentration, the extraction solvent and the part of the plant used. Generally, leaf extracts showed higher antioxidant activities than berry extracts, while the overall antioxidant strength was in the order methanol > water > ethanol in leaf extracts and methanol > ethanol > water in berry extracts. The phenolic content exhibited a positive correlation with the antioxidant activity: DPPH assay showed the highest correlation (r = 0.949), followed by the reducing power assay (r = 0.914) and the lowest for the beta-carotene linoleic acid assay (r = 0.722).

Control of Listeria monocytogenes in goat's milk and goat's jben by the bacteriocinogenic Enterococcus faecium F58 strain.

The bacteriocinogenic Enterococcus faecium F58 strain, a natural goat's jben cheese isolate, lacks decarboxylase activity involved in most biogenic amine formation. It was also sensitive to 13 antibiotics assayed and free of virulence and vancomycin resistance genes. The F58 strain reached the stationary phase after 12 h of growth in sterile goat's milk, and the production of enterocin F-58 (Ent L50) was first detected after 48 h (400 AU/ml), thereafter remaining stable up to 5 days. The effectiveness of the F58 strain in controlling Listeria monocytogenes serovar 4b in reduced fat and whole goat's milk, and in goat's jben has been examined. Coculture experiments of F58-L. monocytogenes in both types of milk demonstrated that listeriae were not eliminated, although reductions by 1 to 4 log units were found. Nevertheless, when the F58 strain was previously inoculated in whole milk and left to grow for 12 h before contamination, the pathogen was completely eliminated after 130 h of coculture. Production of jben cheese contaminated with L. monocytogenes prior to packaging, using preparations of F58-producer strain, caused a significant decrease in the number of viable listeriae, which were undetectable after 1 week of cheese storage at 22 degrees C. Altogether, results from this study suggest that E. faecium F58 strain may be used as an adjunct culture in cheese to control contamination and growth of L. monocytogenes by in situ enterocin production, thus providing an additional hurdle to enhance control of this pathogen.