Antilisterial Activity Research Articles

Bacteriocinogenic Lactococcus lactis subsp. lactis DF04Mi isolated from goat milk: Application in the control of Listeria monocytogenes in fresh Minas-type goat cheese.

Listeria monocytogenes is a pathogen frequently found in dairy products. Its control in fresh cheeses is difficult, due to the psychrotrophic properties and salt tolerance. Bacteriocinogenic lactic acid bacteria (LAB) with proven in vitro antilisterial activity can be an innovative technological approach but their application needs to be evaluated by means of in situ tests. In this study, a novel bacteriocinogenic Lactococcus lactis strain ( Lc . lactis DF4Mi), isolated from raw goat milk, was tested for control of growth of L. monocytogenes in artificially contaminated fresh Minas type goat cheese during storage under refrigeration. A bacteriostatic effect was achieved, and counts after 10 days were 3 log lower than in control cheeses with no added LAB. However, this effect did not differ significantly from that obtained with a non-bacteriocinogenic Lc. lactis strain. Addition of nisin (12.5 mg/kg) caused a rapid decrease in the number of viable L. monocytogenes in the cheeses, suggesting that further studies with the purified bacteriocin DF4Mi may open new possibilities for this strain as biopreservative in dairy products.

Antilisterial Effect of Bacteriocin SH01, Obtained from Enterococcus faecium SH01, in Ground Beef.

From the previous study, Enterococcus faecium SH01 was isolated from mukeunji, an over-ripened kimchi, and it produced bacteriocin SH01. Bacteriocin SH01 showed an inhibitory effect against Listeria monocytogenes ATCC 19111, a bacterial strain causing human listeriosis. Crude bacteriocin SH01 was purified by ammonium sulfate precipitation and its inhibitory activity at two concentrations (500 and 1,000 AU/g) against Listeria monocytogenes ATCC 19111 was investigated in ground beef at increasing temperatures (5, 10, 15, and 20℃) for 8 d. The number of Listeria monocytogenes ATCC 19111 significantly decreased (p<0.05) as the concentration of bacteriocin increased from 500 to 1,000 AU/g. Intrinsic crude protease activities in ground beef were examined and increased as the temperature increased. Experiments varying both the concentrations of added bacteriocin SH01 and temperature demonstrated a maximum inhibition (2.33 log reduction of bacteria) in samples containing 1,000 AU/g of bacteriocin SH01 incubated at 20℃. When the crude bacteriocin SH01 solution (1,280 AU/mL) was incubated with crude protease solutions at different temperatures, its activity decreased by only half (640 AU/mL), as assessed in an agar well diffusion assay. The finding that the antilisterial activity of bacteriocin SH01 increased with temperature can be explained by the fact that higher temperatures increase bacterial membrane fluidity, thereby promoting the cellular penetration of bacteriocin SH01 into L. monocytogenes. Bacteriocin SH01 may be an excellent candidate as a biopreservative for controlling L. monocytogenes growth in ground beef.

Universal cell capture by immobilized antimicrobial peptide plantaricin

Plantaricin-423 is a short antimicrobial peptide and displays bactericidal activities against several foodborne pathogens and spoilage Gram positive bacteria. The goal of this study was to investigate the potential of using immobilized plantaricin for capturing microorganisms on glass arrays. The peptide used for immobilization consists of N-terminal domain of Plantaricin-423 with an additional cysteine (Pln-17C) to form disulfide bonds with thiol groups present on silanized slides. Our results showed that Pln-17C is able to capture all six strains that were tested with varying affinities. The cell capture occurred within five minutes of incubation and the binding level was highest for Listeria innocua followed by other Gram positive strains tested. Pln-17C was also able to capture Escherichia coli with lower affinity, but the binding was significantly lower for Mycobacterium smegmatis compared to other strains. In addition, we have observed that immobilized Pln-17C maintained its anti-listerial activity; however, it did not kill E. coli as expected. Our results demonstrate the feasibility of utilizing antimicrobial peptides in biosensors for pathogen detection and for creating antimicrobial surfaces. Moreover, in combination with other peptides, different target species from food-borne pathogens to biodefense agents can be captured on more stable, economic, and robust platforms.

Phytochemical, Toxicological and Pharmacological Studies of &lt;i&gt;Asiasari Radix&lt;/i&gt; et Rhizoma: A Review

Herba Asar i and Asiasari Radix (AR) have a centuries-old history as a folk medicine in China, Korea and Japan. AR has long been used in combination with other herbs to treat cough, toothache, headache, neuralgia, aphthous stomatitis, gingivitis, chronic bronchitis, asthma and allergies. AR from three species of the genus Asarum: A. heterotropoides Fr. Schmidt var. mandshuricum (Maxim.) Kitag., A. sieboldi i Miq. var. seoulense Nakai and A. sieboldii Miq are recognized as original “ Asiasari Radix et Rhizoma ”. These species do not contain aristolochic acids (nephrotoxins present in the Asarum species) and therefore the roots of AR are recommended for use. Asiasari Radix is rich in volatile oils, phenylpropanoids, terpenoids, flavonoids, glycosides and lignins. The reported toxicological and pharmacological activities of AR, including antifungal, antimicrobial, antilisterial, antiallergic, acarcidal, larvicidal, anti-caries, anti-inflammatory, hepatoprotective, neuroprotective, cytotoxic and anticancer activities suggest its therapeutic potentials in drug discovery. Keywords : Asarum; Asiasarum, Asiasarum heterotropoides var. mandshuricum, Asiasarum sieboldiiHerba Asari, Folk medicine, Pharmacological, Toxicological

Characterization of bacteriocin produced by Enterococcus faecium CN-25 isolated from traditionally Thai fermented fish roe

Enterococcus faecium CN-25 was isolated from a traditionally Thai fermented fish roe, som-kai-pla, and was found to possess enterocin A and B genes. Among the 30 microorganisms tested, the produced bacteriocin exhibited antagonistic activity against Listeria monocytogenes TISTR 1327. The bacterium maximally produced bacteriocin at a concentration of 1828 AU/ml at the beginning of the stationary phase (at 18 h) in the inexpensive rice bran medium. The antilisterial activity of the compound was not affected by heating at 60–100 °C for up to 30 min. High antilisterial activity remained at pH 2. Partially purified CN-25 bacteriocin derived from E. faecium CN-25 completely inhibited the growth of L. monocytogenes at the minimum concentration of 2.38 μg/ml. The compound had no effect on the efflux of ATP from L. monocytogenes but triggered the intracellular hydrolysis of ATP, as evidenced by a decrease in the luminescence of total ATP. The bacteriocin also depleted the transmembrane electrical potential (ΔΨ) but had no effect on the transmembrane pH gradient (ΔpH). Therefore, the partially purified CN-25 peptide may be useful for improving the product safety of fermented fish products.

Biological Characteristics and Safety Examination of Five Enterococcal Strains from Probiotic Products

AbstractFive enterococcal strains (Enterococcus faecalis LS15, PF03, BF10 and SL13 and Enterococcus faecium MM08) were isolated and identified from 130 probiotic products marketed in China. The determined biological characteristics were acid tolerance, bile tolerance, pepsin tolerance, trypsin tolerance, organic acid production and antimicrobial activity. Safety examination of potential virulence factors and antibiotic resistance were also performed. The five isolated strains showed good tolerance to biological barriers in vitro, and lactic acid was the most abundant organic acid (10–11 mg/mL) produced by these strains. The isolates exhibited antilisterial activities. Safety examinations revealed that certain potential virulence factors (ace, gelE and efaA) were harbored in strains LS15, PF03, BF10 and SL13, and all of the isolates exhibited complete or intermediate resistance to gentamicin, ciprofloxacin, erythrocin and tetracycline. Compared with the other isolates, the E. faecium MM08 played the leading role as a probiotic strain. These antilisterial probiotic enterococcal strains had good tolerance to biological barriers, mainly produced lactic acid, exhibited antibiotic resistance traits and could harbor certain virulence factors.Practical ApplicationsThis study aimed to examine the biological characteristics and safety aspects of probiotic enterococcal strains isolated from probiotic products. Five isolates showed good probiotic characteristics, but its safety aspects need to be studied in the future.

Biocontrol of Listeria monocytogenes by lactic acid bacteria isolated from brewer's grains used as feedstuff in Argentina

Brewer's grains are the most important by-product of the brewery industry and it is mostly used as a protein and energy source in animal nutrition. Listeria monocytogenes is a food-borne pathogen can cause invasive diseases such as meningoencephalitis, sepsis, abortion, and gastroenteritis in humans and several animal species. The aim of this work was to study the antilisterial activity of lactic acid bacteria (LAB) isolated from brewer's grains. The incidence of Listeria spp. in brewer's grains was 3.12%. Twenty-one LAB inhibited the growth of the eight strains of L. monocytogenes. The mean inhibition halo of cell free supernatants of LAB ranged between 11.5 and 24.5 mm. The isolation of lactic acid bacteria with antilisterial activity from brewer's grains is promising based on their capacity to produce antimicrobial compounds. The production of antimicrobial metabolites by LAB in the substrate would generate an unfavorable environment for the growth of the pathogenic bacterium under study.

The use of lysozyme to prepare biologically active chitooligomers

Two types of crustacean commercial chitosans (CS1, CS2) were dissolved in lactic acid solutions, hydrolysed by lysozyme and finally fractioned by methanol solutions into two parts containing chito-oligomers (CS-O1, CS-O2). The antioxidant power and antimicrobial properties of both fractions were studied and compared with non-hydrolysed CS1 and CS2. The antioxidant properties were determined by the ferric ion reducing antioxidant power (FRAP) method while the bioactive properties were evaluated against a strain of Listeria monocytogenes. CS-O obtained from the solid fraction of the chito-oligomers solid fractions treated with 90% methanol showed the highest reducing power. Microbiological tests showed that CS-O exhibit higher antilisterial activity than CS.

Antilisterial activity and physical-mechanical properties of bioactive caseinate films

Antimicrobial films were formulated with sodium caseinate (C), glycerol and antimicrobial substances (AM) produced by Streptococcus infantarius. The antilisterial activity of the films was evaluated using Listeria monocytogenes as test microorganism and two incubation conditions: T = 35°C, 32 ± 10% RH and T = 4°C, 98 ± 10% RH. A comparison of the antimicrobial action was made with caseinate films carrying equivalent activity units of commercial nisin (Nis). At 35°C and 32% RH, AM increased the lag-phase and inhibited 80% of the growth of L. monocytogenes. At 4°C and 98% RH, C-Nis and C-AM films extended the lag-phase of the bacterial growth up to 11 and 38 days, respectively. AM showed a higher antilisterial effect than nisin at both incubation conditions. The incorporation of AM or Nis did not produce significant differences in the barrier properties of the films, but AM acted as an additional plasticizer into the films.

Antilisterial Activity of Bacteriocin HY07 from Enterococcus faecium HY07 Isolated from Chinese Sausages

In this study, we present a partial purification of bacteriocin HY07 from E. faecium HY07 isolated from Chinese sausage, which exhibited antimicrobial activity to Listeria, Salmonella, Shigella, Staphylococcus, Clostridium, and Bacillus. E. faecium HY07 was shown to lack haemolytic activity and found to be sensitive to tested antibiotics (rifampicin, vancomycin, teicoplanin, and penicillin G). Bacteriocin HY07 was sensitive to proteolytic enzymes, but stable between pH 2.0–10, and heat resistance (15 min at 121°C). In addition, production of bacteriocin HY07 started at the early exponential phase and reached its maximum at the stationary phase, and exerted bacteriostatic effect to Listeria monocytogenes 54002. Bacteriocin HY07 was estimated below 6.5 kDa by tricine-SDS-PAGE. Growth in the presence of tryptone stimulated bacteriocin production. However, lower activity was recorded when the bacteria were grown in the presence of meat extract or yeast extract. MRS broth supplemented with 20 g/L glucose yielded bacteriocin levels of 160 AU/mL, but the production of bacteriocin HY07 was repressed by more than 50% when glucose exceeded 30 g/L. Growth in the presence of maltose, fructose, fructose, sucrose, lactose, and galactose yielded lower activity of bacteriocin. MRS medium supplemented with glycerol repressed bacteriocin production.

Phyto-Chemical Screening and Anti Listerial Activity of Annona Muricata (L) Leaf Extract

Annona muricata is a potent medicinal plant with wide range of therapeutic activity. Various parts of this plant have immense beneficial and curative properties. The phyto-chemical screening of the leaf extract was performed using aqueous and methanolic extracts that showed the presence of all major primary and secondary metabolites and anti-oxidant trait. The aqueous extract was then subjected to anti listerial activity that showed significant results.

Antagonistic Effect of Pseudomonas sp. CMI-1 on Foodborne Pathogenic Listeria monocytogenes.

Bacterial isolates derived from food or raw food materials of animal origin were screened for potential antagonistic activity against foodborne pathogenic Listeria monocytogenes. Using the agar spot method, ten out of the 94 tested bacteria showed antilisterial activity. All of the antagonistic isolates identified by sequence analysis as strains of the genus Pseudomonas were able to inhibit the growth of all the examined Listeria species including the ruminal pathogenic L. ivanovii and the opportunistic human pathogenic L. innocua. Pseudomonas sp. CMI-1 had the highest inhibitory effect on the growth of different Listeria strains. Co-culturing studies revealed that the inhibition of L. monocytogenes could not be achieved efficiently. Although the population of the Pseudomonas sp. CMI-1 strain increased by up to 10 orders of magnitude during 2 days of culturing period at 20 °C in the presence of L. monocytogenes, the cell count of the pathogen also increased by approx. 6 orders of magnitude. At the same time, appropriate inhibition of cell-free supernatants generated from 6-day-old cultures of Pseudomonas sp. CMI-1 was observed. The inhibitory compound of this antagonistic strain is presumably a chromopeptide siderophore, whose activity and production can be affected by iron supplementation, and which had an absorption maximum typical of siderophores of fluorescent Pseudomonas species. Production of the antilisterial substance was influenced by the oxygen concentration, as in static cultures the concentration of the siderophore was higher than in shake flask cultures.

Antilisterial activity of bacteriocinogenic Pediococcus acidilactici HA6111-2 and Lactobacillus plantarum ESB 202 grown under pH and osmotic stress conditions

Bacteriocin producing lactic acid bacteria (LAB) cultures can be used as biopreservatives in fermented food products; thus the food industry is interested in stable cultures that produce bacteriocins consistently. Inhibtion of Listeria spp. by bacteriocinogenic Pediococcus acidilactici and Lactobacillus plantarum (both isolated from fermented meats) was investigated under conditions of stress induced by low pH and high salt concentrations. Listeria monocytogenes serogroup IIb (from cheese), L. monocytogenes serogroup IVb (from cheese), L. monocytogenes serogroup IIb (from ground beef) and Listeria innocua NCTC 11288 were used as target strains. P. acidilactici and Lb. plantarum demonstrated antilisterial activity under the stress conditions investigated (pH 3.5; pH 8.5; 7.5% NaCl). However, activity was dependent on the stress conditions applied and on the target organism. L. monocytogenes serogroup IIb (from ground beef) and L. innocua C 11288 were, respectively the most sensitive and the most resistant to the cell-free supernatants produced by the LAB investigated.

Inhibitory Effect of Isolated Lactic Acid Bacteria from Scomberomorus commerson Intestines and their Bacteriocin on Listeria innocua

ABSTRACT- Lactic acid bacteria are commonly found in the gastrointestinal tract of various endothermic animals and humans, in milk, dairy and seafood products and on some plant surfaces. The aim of this study was to investigate the inhibitory effect of isolated lactic acid bacteria from intestines of narrow-barred Spanish mackerel (Scomberomorus commerson) on Listeria innocua growth. Five strains of lactic acid bacteria (LAB) were isolated. Lactobacillus buchneri, Lactococcus lactis, Lactobacillus acidophilus, Lactobacillus fermentum and Sterptococcus salivarius strains were presumptively identified by biochemical and physiological tests. Anti-listerial activities of these isolates and their cell free supernatants (CFS) were evaluated using agar spot tests, agar well diffusion assays and BHI broth. The results revealed that all cultures and their cell free supernatants were able to inhibit L. innocua growth. Furthermore, the study showed that wastes of this kind of warm water sea fish, have antagonistic activities against L. innocua and can be potentially used as a free source of LAB.

Addition to Thermized Milk of Lactococcus lactis subsp. cremoris M104, a Wild, Novel Nisin A–Producing Strain, Replaces the Natural Antilisterial Activity of the Autochthonous Raw Milk Microbiota Reduced by Thermization

Recent research has shown that mild milk thermization treatments routinely used in traditional Greek cheese production are efficient to inactivate Listeria monocytogenes and other pathogenic or undesirable bacteria, but they also inactivate a great part of the autochthonous antagonistic microbiota of raw milk. Therefore, in this study, the antilisterial activity of raw or thermized (63°C, 30 s) milk in the presence or absence of Lactococcus lactis subsp. cremoris M104, a wild, novel, nisin A-producing (Nis-A+) raw milk isolate, was assessed. Bulk milk samples were taken from a local cheese plant before or after thermization and were inoculated with a five-strain cocktail of L. monocytogenes (approximately 4 log CFU/ml) or with the cocktail, as above, plus the Nis-A+ strain (approximately 6 log CFU/ml) as a bioprotective culture. Heat-sterilized (121°C, 5 min) raw milk inoculated with L. monocytogenes was used as a control treatment. All milk samples were incubated at 37°C for 6 h and then at 18°C for an additional 66 h. L. monocytogenes grew abundantly (>8 log CFU/ml) in heat-sterilized milk, whereas its growth was completely inhibited in all raw milk samples. Conversely, in thermized milk, L. monocytogenes increased by 2 log CFU/ml in the absence of strain M104, whereas its growth was completely inhibited in the presence of strain M104. Furthermore, nisin activity was detected only in milk samples inoculated with strain M104. Thus, postthermal supplementation of thermized bulk milk with bioprotective L. lactis subsp. cremoris cultures replaces the natural antilisterial activity of raw milk reduced by thermization.

Controlled Release Properties of Zein–Fatty Acid Blend Films for Multiple Bioactive Compounds

To develop edible films having controlled release properties for multiple bioactive compounds, hydrophobicity and morphology of zein films were modified by blending zein with oleic (C18:1)Δ⁹, linoleic (C18:2)Δ(9,12), or lauric (C₁₂) acids in the presence of lecithin. The blend zein films showed 2-8.5- and 1.6-2.9-fold lower initial release rates for the model active compounds, lysozyme (LYS) and (+)-catechin (CAT), than the zein control films, respectively. The change of fatty acid chain length affected both CAT and LYS release rates while the change of fatty acid double bond number affected only the CAT release rate. The film morphologies suggested that the blend films owe their controlled release properties mainly to the microspheres formed within their matrix and encapsulation of active compounds. The blend films showed antilisterial activity and antioxidant activity up to 81 μmol Trolox/cm². The controlled release of multiple bioactive compounds from a single film showed the possibility of combining application of active and bioactive packaging technologies and improving not only safety and quality but also health benefits of packed food.

Occurrence of antilisterial structural bacteriocins genes in meat borne lactic acid bacteria

Abstract The ability to inhibit the growth of Listeria cells and the presence of bacteriocin encoding genes was examined in 115 LAB strains isolated from Argentinean vacuum-packaged beef and different traditional fermented sausages. Lactobacillus (L) sakei, Lactobacillus (L) curvatus and Enterococcus (E) faecium showed a great inhibition of all Listeria strains evaluated while Pediococcus (P) acidilactici and Lactobacillus (L) plantarum demonstrated a limited or absent antilisterial activity. Both L. curvatus and L. sakei carried the sppA, sppQ and sapA structural genes, encoding for sakacin P, sakacin Q and curvacin A bacteriocins, respectively. Whilst L. curvatus exhibited a higher occurrence of these genes, L. sakei strains were more effective at inhibiting Listeria (L) strains, Listeria monocytogenes UC8159 and Listeria innocua 7 being the most sensitive to these bacteriocins. Among analyzed E. faecium strains, the wide distribution of entA, entB and entP genes accounted for the high antilisterial activity particularly observed against L. monocytogenes FBUNT. The structural gene plantEF was mostly present in Lactobacillus plantarum strains and no pedA gene was found in P. acidilactici evaluated strains. The antilisterial potential of L. sakei and E. faecium offers great possibilities for the meat industry as biopreservative cultures, although more studies are needed in order to conclude about this issue.

Extraction, antioxidant and antilisterial activities of polysaccharides from the flower of viper's bugloss

The objective of the present research was to investigate the effect of microwave-assisted extraction (MAE) conditions on the extraction yield, antioxidant properties and antilisterial activities of the polysaccharides from the flowers of viper's bugloss (Echium vulgare L.). The four extraction variables, time (40–100min), microwave power (200–800W), temperature (30–70°C), and the ratio of water to raw material (10–70), were optimized using response surface methodology. The experimental data were matched to a second-order polynomial equation. The optimal conditions for MAE of polysaccharides (EVFP) were time 73.8min, microwave power 769.2W, temperature 42.3°C and the ratio of water to raw material 61.4, where the actual yield of EVFP 25.11±0.87% was obtained (versus the value predicted by the model 25.36%). The results indicated that EVFP has significant radical (·OH and ·DPPH) scavenging abilities in vitro assay. Moreover, the antilisterial activity was confirmed against four species of Listeria. EVFP, at a concentration of 5mg/mL, demonstrated great antilisterial properties against Listeria ivanovii and Listeria monocytogenes, with inhibition zones of 10.76±0.32mm and 8.64±0.47mm, respectively.

Antilisterial activity of lactic acid bacteria against Listeria monocytogenes strains originating from different sources

Eight individual bacteriocin-producing lactic acid bacteria (LAB) strains and three bacteriocin-non-producing cheese starter cultures were evaluated for their ability to inhibit the growth of six Listeria monocytogenes strains, originating from the guinea-pig lymph nodes, raw cow milk, and manufacturing dairy equipment. Results showed that either live cells or cell-free neutralised supernatant (CFNS) and/or heated CFNS of six individual LAB strains (Lcc. lactis subsp. lactis CCDM 416 and NIZO R5, Lbc. plantarum HV 11 and DC 1246, P. acidilactici HV 12, and Ent. mundtii CCM 1282) and one starter culture (DELVO-ADD&lt;sup&gt;&amp;reg;&lt;/sup&gt; 100-X DSF) were effective in the suppression of at least one listeria strain. Neither any individual LAB strain nor starter culture was antagonistic toward all studied L. monocytogenes strains, indicating diverse sensitivity/resistance among L. monocytogenes strains to antimicrobial compounds of LAB. The significant susceptibility of listerias isolated from raw milk and dairy equipment together with the strong antilisterial activity of DELVO-ADD&lt;sup&gt;&amp;reg; &lt;/sup&gt;100-X DSF could be applied in dairy technology, where commonly used starter cultures could play both the biopreservative and fermentation role. &amp;nbsp;

Sakacin Q produced by Lactobacillus curvatus ACU-1: Functionality characterization and antilisterial activity on cooked meat surface

This work was conducted to evaluate the antilisterial activity of sakacin Q produced by Lactobacillus curvatus ACU-1 on the surface of cooked pork meat. A genetic re-characterization of the producer strain and a study of the structural genes involved in bacteriocin production were carried out as complementary data. Studies indicated that the bacteriocin was not attached to the producer cells favoring pre-purifications steps. Bacteriocin effectiveness was not compromised by adsorption to meat and fat tissues. Several ways of dispensing the bacteriocin onto the meat surface, namely cell culture, cell free supernatant (CFS), a mixture of both and freeze-dried reconstituted CFS, were investigated. The use of the latter was the most effective one to control Listeria growth within studied systems. L. curvatus ACU-1 and its bacteriocin presented promising technological characteristics that made them suitable for meat biopreservation.