Antimicrobial and antioxidant activity of crude onion (Allium cepa,L.) extracts

Antioxidant and antimicrobial activity of the ethyl acetate and water subfractions of methanolic extracts of three Spanish onion varieties were assayed. Flavonoids were mainly present in ethyl acetate subfraction being 34.92 ± 0.75, 7.95 ± 0.16, 0.38 ± 0.01 μmol of rutin eq. g^?1 D.W. and its antioxidant capacity was 74.86 ± 1.77, 24.59 ± 0.67, 4.55 ± 0.44 μmol Trolox g^?1 D.W. of Grano de Oro, Fuentes de Ebro and Calçot de Valls varieties, respectively. The antimicrobial activity of flavonol standards and onion extracts was evaluated against some food spoiler microorganisms. Quercetin and kaempferol were inhibitory against gram positive bacteria such as Bacillus cereus, Staphylococcus aureus, Microcroccus luteus and Listeria monocytogenes. Gram negative bacteria Escherichia coli and Pseudomonas aeruginosa were less sensible to the antimicrobial effect of both flavonol standards and Candida albicans was totally resistant. Among the onion extracts tested only ethyl acetate subfraction showed antimicrobial inhibition.     

Inhibition of Clostridium sporogenes PA 3679 and Natural Bacterial Flora of Cooked Vacuum-Packaged Bratwurst by Sodium Acid Pyrophosphate and Sodium Tripolyphosphate With or Without Added Sodium Nitrite

Survival and growth of inoculated Clostridium sporogenes PA3679 and natural aerobic and anaerobic bacterial flora were studied in refrigerated (5°C) and subsequently temperature abused (24–25°C), cooked, vacuum-packaged bratwurst containing 0.5% sodium acid pyrophosphate (SAPP) or sodium tripolyphosphate (STPP) with or without sodium nitrite. Phosphates alone or combined with nitrite did not affect aerobic bacterial counts but resulted in reduced clostridial and anaerobic counts at 5°C. Upon temperature abuse, inhibition of all bacteria by SAPP was significant (P<0.05) for up to 48 hr and greatly enhanced by 100 ppm but not by 50 ppm sodium nitrite, whereas STPP lost its antimicrobial properties after 24 hr. Soluble orthophosphate levels had a positive correlation with bacterial inhibition in SAPP-treated bratwurst.     

Thyme Oil Encapsulated in Halloysite Nanotubes for Antimicrobial Packaging System

An antimicrobial capsule releasing thyme oil was developed using modified halloysite nanotubes (HNTs). In order to increase the pore volume, HNTs were treated with 5.0 mol/L NaOH solution, which resulted in the encapsulation of more thyme oil molecules inside the HNTs. The morphology of the raw HNTs and NaOH‐treated HNTs (N‐HNTs) was characterized using transmission electron microscopy and nitrogen adsorption‐desorption analysis. The loading capacity increased from 180.7 ± 12.7 to 256.4 ± 16.7 mg thyme oil/g HNT after the NaOH treatment. The aerial release characteristics of thyme oil from both the HNT capsules were investigated in a closed‐package atmosphere system at 4, 25, and 40 °C. The antimicrobial activity of the capsule against Escherichia coli O157:H7 was determined using the vapor phase assay. Moreover, the antimicrobial effects of the capsule against E. coli O157:H7, total mesophilic aerobic bacteria (MAB), and molds and yeasts (MY) on the surfaces of cherry tomatoes were investigated at 4 and 25 °C for 5 d. When the cherry tomatoes were exposed to the thyme oil‐loaded N‐HNT capsule, the number of E. coli O157:H7, MAB, and MY significantly reduced during storage.     

Inhibitory effect of kiam (Cotylelobium lanceotatumcraih.) wood extract on gram-positive food-borne pathogens and spoilage micro-organisms

Water extract from kiam (Cotylelobium lanceotatumcraih.) wood was investigated for inhibitory and lethal activity against pathogenic bacteria and micro-organisms isolated from sugar palm sap. Bacteria representing six generaAcetobacter,Flavobacterium,Lactobacillus,Leuconostoc,MicrococcusandSaccharomycesisolated from sap were inhibited on agar media to which a 0.2% (wt/v) water extract of kiam wood saw dust was applied. Extract inhibited growth ofListeria monocytogenes, toxigenicStaphloccoccus aureusand enterotoxigenicBacillus cereusbut not enterohemorrhagicEscherichia coli0157:H7 orSalmonella. The behavior ofL. monocytogenesinoculated onto shredded raw cabbage which was then treated with 0, 0.5 or 5% solutions of wood kiam extract and subsequently stored at 5°C for up to 5 days was determined. Populations of aerobic mesophiles and psychrotrophic micro-organisms were also monitored. Significantly (P=0.05) reduced populations ofL. monocytogeneswere detected in cabbage treated with 0.5 or 5.0% extract and held for 2 or 5 days. Treatment with kiam extract retarded the rate of growth of aerobic mesophiles and psychrotrophic micro-organisms naturally present on cabbage. Treatment with 5.0% extract had a sustained lethal effect during a 5 day test period. Further research is warranted to characterize the compound(s) in kiam wood extract responsible for inhibitory or lethal activity against spoilage micro-organisms and other pathogenic bacteria that may be present in foods.     

LACTOBACILLUS CURVATUS PRODUCES A BACTERIOCIN-LIKE AGENT ACTIVE AGAINST GRAM-NEGATIVE PATHOGENIC BACTERIA

Isolates from fermented foods were screened for antimicrobial activity against gram‐negative bacteria. The most active isolate was identified as a Lactobacillus curvatus by biochemical analysis and ribotyping, and the isolate was designated as OSY‐HJC6. Lactobacillus curvatus OSY‐HJC6 was further tested for intracellular and extracellular production of antimicrobial agents. A reduction of > 8 log₁₀ cfu/mL was observed when cell suspensions of Salmonella enterica serovar Enteritidis and Escherichia coli O157:H7 were treated with equal volumes of Lb. curvatus culture supernatant. Gram‐positive bacteria were not sensitive to the culture supernatant, but antimicrobial activity was detected when the cell extract was tested against several gram‐positive and gram‐negative bacteria. Culture supernatant and cell extract retained the antimicrobial activity after heating at 60–100C for 10 min but not after protease treatment. The cell extract of Lb. curvatus retarded the growth of E. coli p220 in broth medium and food extracts (i.e., bacteriostatic action) but showed bactericidal activity against the bacterium in phosphate buffer.     

Purification and characterization of pedioxanthin (carotenoid pigment) produced by Pediococcus pentosaceus N33 strain isolated from pickles

Forty-two lactic acid bacteria were isolated from 28 pickles and yoghurt samples, and screened for their antimicrobial efficacy against certain multidrug resistant (MDR) bacteria using well diffusion method. A strain Pediococcus pentosaceus N33 (MF062087) showed the best inhibitory effects against both Brevibacillus brevis H18 (MG637284) and Lysinibacillus fusiformis R29 (MG637285). Pediococcus pentosaceus N33 strain produced high thermostable antimicrobial compound as indicated by heat treatment between 60 and 100°C for 20 min as well as at 121°C for 15 min. It is a proteinaceous compound highly active at acidic pH (2–6). The antimicrobial compound was extracted and precipitated by 70% ammonium sulfate and finally fractionated using Sephadex G₅₀ column. The molecular weight of pure compound was 10 kDa using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The spectroscopic analysis based on UV, IR, NMR and MS analyses were used to characterize and identify the pure antimicrobial compound. From the characterization and identification of this inhibitory compound, it was observed that the target compound contains carotenoid pigment in addition to protein. This carotenoid pigment was identified as pedioxanthin which is the first observed from this strain. Our results evaluated the potential activity of Pediococcus pentosaceus N33 strain as a probiotic agent and its potential contribution for food industry and pharmaceutical applications.     

Antioxidant compounds in edible brown seaweeds

Seaweeds are an excellent source of compounds with biological activity. Among the bioactive substances identified, antioxidants have received particular interest due to their beneficial effects on health. In the present study, the total phenolic content and the pigment contents in edible seaweeds were evaluated. The total phenolic content was determined by Folin-Ciocalteu’s method for four species of brown algae included Himanthalia elongata, Laminaria sp., Laminaria saccharina and Undaria pinnatifida. The total polyphenol content varied between 1.3 and 10.0 g phloroglucinol/kg wet weight of sample. The components responsible of the colour (carotenoids and chlorophylls) of the seaweeds were evaluated by using a spectrophotometric method. In addition, pigments were separated and identified by on line HPLC coupled with UV–Vis and fluorescence detectors and confirmed by liquid chromatography coupled to mass spectrometry (LC–MS APCI). Fucoxanthin, β-carotene, chlorophyll a and phaeophytin a were identified in the samples analysed.     

Antimicrobial activity of food-compatible plant extracts and chitosan against naturally occurring micro-organisms in tomato juice

BACKGROUND: Chitosan (AC) and five hydroalcoholic extracts from Lithospermum erythrorhizon (SE), Rheum palmatum (RE), Thymus vulgaris (AT), Lippia citriodora (PLX) and a mixture of Rosmarinus officinalis, Salvia lavandulifolia and Thymus mastichina (LA) were tested for antimicrobial activity against bacteria, yeasts and filamentous fungi using two broth dilution methods. The effects of adding single extracts on naturally occurring micro‐organisms and sensory qualities of raw tomato juice were also evaluated. RESULTS: SE extract exhibited the strongest activity, with minimum inhibitory concentrations (MICs) of 100–400 µg mL^?1 for Gram‐positive and 1600–3200 µg mL^?1 for Gram‐negative bacteria. Enterobacter aerogenes showed the greatest susceptibility to AC (MIC 1600 µg mL^?1). Lethal effects of extracts and AC were achieved at a minimum bactericidal concentration (MBC)/MIC ratio of 2 in 88% of assays. SE and RE extracts and AC also exhibited antifungal effect against yeasts, but they had no activity on filamentous fungi. Control and 100 mg L^?1 SE‐added tomato juices did not differ in acceptance, but this SE concentration was not effective in the control of microbial load throughout cold storage. CONCLUSION: Results confirm the antimicrobial potential of the plant extracts, but additional research is needed until the agents responsible for the activities have been determined in order to use them as natural constituents of multiple‐barrier food preservation systems. Copyright © 2012 Society of Chemical Industry     

Application of Green Technology for the Acquisition of Extracts of Araçá (Psidium grandifolium Mart. ex DC.) Using Supercritical CO2 and Pressurized Ethanol: Characterization and Analysis of Activity

Brazil is home to a wide variety of flora, including several lesser known species, such as araçá that were processed in this study using two green technologies consecutively: supercritical fluid extraction (SFE) for nonpolar fraction and pressurized liquid extraction. For polar fraction, the experiments followed a central composite design involving ethanol as solvent, with temperature and static time in each bath as independent variables. Both extracts were analyzed for antioxidant and antimicrobial activities. Total phenolics content (TPC) was determined for all ethanol extracts. In the araçá essential oil (AEO) obtained by SFE, the extraction yield was 2.33%. The three major compounds of AEO were α‐pinene (20.75%), p‐cymene (20.50%), and o‐cymene (20.05%). In ethanol extracts, the high yield (14.49%) was obtained at 74 °C/6 min and the major TPC (136.95 mg GAE/100 g) at 60 °C/9 min. Ethanol extracts presented good antioxidant activity (EC₅₀ = 6.37 mg/mL) at 74 °C/6 min. AEO was unable to reduce DPPH? concentration by 50%. Both extract types presented an inhibitory effect against Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus cereus, while only the ethanol extracts presented effect against Listeria monocytogenes. This work had the aim to present the innovation of the use of a whole typical Brazilian fruit that gives rise to extracts with excellent properties for employment in both the pharmaceutical and food industries.     

Bio-screening of a few green seaweeds from India for their cytotoxic and antioxidant potential

BACKGROUND: It has been evidenced in several epidemiological studies that seaweeds when consumed as diet protect against several chronic oxidative stress‐related diseases. Seaweeds, raw, cooked, or dried, are used as food in many cultures, although not very popularly in India. Globally, several studies have indicated that seaweeds are a rich source of phenolic compounds and have antioxidant properties. In the present study, we screened methanolic extracts (MEs) of five species of green seaweeds commonly found in India for their cytotoxic activity by brine shrimp lethality assay and antioxidant properties using various in vitro assays, including 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging, reducing power and metal ion chelating assays. RESULTS: A markedly variable, dose‐dependent activity was observed in all the seaweed extracts relative to their total phenolic content. Statistical analysis indicated a significantly strong correlation between the DPPH radical scavenging activity and total phenolic content (R² = 0.88, P < 0.05) as well as reducing power and total phenolic content (R² = 0.99, P < 0.01) of the dry MEs. Also, a very poor correlation between total phenolic content and metal chelating activity (R² = 0.13, P > 0.05) was noted. None of the seaweed extracts were potently cytotoxic. CONCLUSION: The underlying results endorse seaweeds as a rich, novel source of antioxidant compounds needing systemic exploration. Copyright © 2011 Society of Chemical Industry     

Effectiveness of Zataria multiflora Boiss essential oil and grape seed extract impregnated chitosan film on ready-to-eat mortadella-type sausages during refrigerated storage

BACKGROUND: The effectiveness of chitosan films containing Zataria multiflora Boiss essential oil (ZEO) (5 and 10 g kg^?1) and grape seed extract (GSE) (10 g kg^?1) on lipid oxidation and microbial (lactic acid bacteria, aerobic mesophiles and inoculated Listeria monocytogenes) characteristics of mortadella sausage at 4 °C for 21 days was evaluated. The release of total phenolics (TPs) into sausage was also assessed. RESULTS: All films exhibited antibacterial activity against L. monocytogenes on agar culture media. Chitosan films containing ZEO were the most effective on the growth of bacteria. The growth of L. monocytogenes was significantly inhibited by ZEO‐GSE containing films especially during storage of the sausages for 6 days. Aerobic mesophiles and lactic acid bacteria were the most sensitive and resistant groups to films by 0.1–1.1 and 0.1–0.7 log cycles reduction, respectively. Sausages wrapped by 10 g kg^?1 GSE + 10 g kg^?1 ZEO films had the lowest degrees of lipid oxidation, which was 23% lower than the control. The TPs of ZEO films decreased to zero after 6 days, whereas TPs of GSE films followed a slight decrease during the storage. CONCLUSION: Antimicrobial/antioxidant chitosan film could be developed by incorporating GSE and ZEO for extending the shelf life of mortadella sausage. Copyright © 2011 Society of Chemical Industry     

Antimicrobial effects of onion (<Emphasis Type="Italic">Allium cepa</Emphasis> L.) peel extracts produced via subcritical water extraction against <Emphasis Type="Italic">Bacillus cereus</Emphasis> strains as compared with ethanolic and hot water extraction

In this study, the antimicrobial effects of an onion peel extract prepared using subcritical water extraction (SWE) were assessed for possible development into new bio-functional materials. The extraction temperatures were controlled to 110 and 160°C. At 0.15, 0.3, 0.6, and 1.2 mg extract/mL of broth, the growth inhibition and bactericidal activity of SWE extracts against Bacillus cereus KCCM 40935 and KCCM 11341 were compared with those of ethanol and hot-water extracts. In the case of B. cereus KCCM 40935, it appeared that over 0.6 mg/mL of SWE (110°C) extract exerted a bactericidal effect, and 1.2 mg/mL of SWE (160°C) extract exerted a bacteriostatic effect during culturing, and also that B. cereus KCCM 11341 was more resistant than B. cereus KCCM 40935. Furthermore, our results demonstrated that the death time of 10⁷ CFU/mL of B. cereus KCCM 40935 treated with SWE (110°C) extract at 1.2 mg/mL was 60 min at maximum in 0.8% NaCl. Additionally, the cells damaged by SWE extract were observed with a SEM. It was suggested that an extract of onion peels prepared via SWE (110°C) could be used as a functional biomaterial for the food or pharmaceutical industries.     

Functional characterization of pressurized liquid extracts of Spirulina platensis

Three different parameters (temperature, solvent, and extraction time) were studied regarding to pressure liquid extraction (PLE) of antioxidant and antimicrobial compounds from Spirulina platensis. Two different antioxidant methods, β-carotene bleaching method and DPPH^• (2,2-Diphenyl-1-picrylhydrazyl hydrate) free radical scavenging assay, were used to determine the optimal PLE conditions for antioxidants extraction. The selected conditions were as follows: extraction temperature equal to 115 °C, extraction time equal to 15 min and ethanol as extracting solvent. The main antioxidant compounds found in this extract were identified as zeaxanthin, a myxoxanthophyll-like compound and very polar phenolic compounds. Moreover, antimicrobial activity of different PLE fractions was tested against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 11775, Candida albicans ATCC 60193, and Aspergillus niger ATCC 16404. Data obtained showed the hexane and petroleum ether extracts were slightly more active than ethanolic extracts. As for water extracts, none of them were active against the microorganisms tested. Data indicated that both 115 and 170 °C were the best extraction temperatures conditions in order to optimize the extraction of antimicrobial compounds, whereas 9 min was the optimal extraction time. Besides, C. albicans was the most sensitive microorganism to all Spirulina PLE extracts.     

Effect of Poly- and Pyrophosphates on the Natural Bacterial Flora and Inoculated Clostridium sporogenes PA 3679 in Cooked Vacuum packaged Bratwurst

Survival and growth of inoculated Clostridium sporogenes PA 3679 and of natural aerobic and anaerobic bacterial flora were studied in cooked, vacuum packed bratwurst containing 0.5% phosphates during refrigerated (5°C) and subsequent temperature abuse storage (24°C). Sodium acid pyrophosphate (SAPP), sodium tripolyphosphate (STPP), tetrasodium pyrophosphate (TSPP) and sodium polyphosphate glassy (SPG) were tested. No significant bacterial inhibition by any phosphate was observed during refrigerated storage, nor was there appreciable growth in the control bratwurst. However, SAPP significantly inhibited aerobic and anaerobic bacteria (including C. sporogenes) upon temperature abuse, followed in effect by TSPP and STPP. Cooking to 65.5°C helped retain antimicrobial properties of phosphates to some extent. Enzymatic hydrolysis of phosphates is postulated as a major factor in loss of antimicrobial properties of phosphates in processed meats.     

Phytochemical Profiles and Antimicrobial Activity of Aromatic Malaysian Herb Extracts against Food‐Borne Pathogenic and Food Spoilage Microorganisms

Preliminary phytochemical and flavonoid compounds of aqueous and ethanolic extracts of 6 aromatic Malaysian herbs were screened and quantified using Reverse‐Phase High Performance Liquid Chromatography (RP‐HPLC). The herbal extracts were tested for their antimicrobial activity against 10 food‐borne pathogenic and food spoilage microorganisms using disk diffusion assay. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)/minimum fungicidal concentration (MFC) of herbal extracts were determined. In the phytochemical screening process, both aqueous and ethanolic extracts of P. hydropiper exhibited presence of all 7 tested phytochemical compounds. Among all herbal extracts, the aqueous P. hydropiper and E. elatior extracts demonstrated the highest antibacterial activity against 7 tested Gram‐positive and Gram‐negative bacteria with diameter ranging from 7.0 to 18.5 mm and 6.5 to 19 mm, respectively. The MIC values for aqueous and ethanolic extracts ranged from 18.75 to 175 mg/mL and 0.391 to 200 mg/mL, respectively while the MBC/MFC values for aqueous and ethanolic extracts ranged from 25 to 200 mg/mL and 3.125 to 50 mg/mL, respectively. Major types of bioactive compounds in aqueous P. hydropiper and E. elatior extracts were identified using RP‐HPLC instrument. Flavonoids found in these plants were epi‐catechin, quercetin, and kaempferol. The ability of aqueous Persicaria hydropiper (L.) H. Gross and Etlingera elatior (Jack) R.M. Sm. extracts to inhibit the growth of bacteria is an indication of its broad spectrum antimicrobial potential. Hence these herbal extracts may be used as natural preservative to improve the safety and shelf‐life of food and pharmaceutical products.     

ANTIMICROBIAL SCREENING OF DECALEPIS HAMILTONII WIGHT AND ARN. (ASCLEPIADACEAE) ROOT EXTRACTS AGAINST FOOD-RELATED MICROORGANISMS

The antimicrobial activity of petroleum ether, benzene, chloroform, ethyl acetate and methanol extracts of Decalepis hamiltonii Wight and Arn. (Asclepiadaceae) against 15 different food‐related microorganisms was evaluated. Among the solvent extracts, methanolic and petroleum ether extracts are the most active exhibiting growth inhibition of 11 and nine of the 15 organisms, respectively. The inhibitory activity was comparable with the respective standards. The results suggest that methanolic and petroleum ether extracts can be used for the bioactivity‐guided isolation of novel antimicrobials which prevents food spoilage.     

Antimicrobial activity of Yerba Mate (Ilex paraguariensis) aqueous extracts against Escherichia coli O157:H7 and Staphylococcus aureus

Abstract: Bioactive compounds from natural plant sources are becoming increasingly important to the food industry. Ilex paraguariensis is used in the preparation of a widely popular tea beverage (Yerba Mate) in the countries of Uruguay, Paraguay, Argentina, and Brazil. In this study, extracts of 4 brands of commercial tea, derived from the holly plant species, Ilex paraguariensis, were evaluated for their ability to inhibit or inactivate bacterial foodborne pathogens. The ultimate goal was to evaluate potential use of the extracts in commercial applications. Dialyzed aqueous extracts were screened for antimicrobial activity against Escherichia coli O157:H7 and Staphylococcus aureus. S. aureus was found to be the more sensitive to extracts than E. coli O157:H7. Minimum bactericidal concentrations (MBCs) were determined to be approximately 150 to 800 μg/mL and 25 to 50 μg/mL against E. coli O157:H7 and S. aureus, respectively. A Uruguayan brand had reduced activity against E. coli O157:H7 compared to the Argentinean brands tested. It was concluded that Yerba Mate could be used as a potential antimicrobial in foods and beverages against these pathogenic bacteria. Practical Application: Soluble extracts from Yerba Mate are natural antimicrobials that can be incorporated into food products to achieve longer shelf life.     

Antibacterial and antioxidant effects of five spice and herb extracts as natural preservatives of raw pork

BACKGROUND: The aim of this study was to find natural spice and herb extracts with antibacterial and antioxidant capacities that could be potentially used as natural preservatives in raw pork. RESULTS: The inhibitory effects of cinnamon stick, oregano, clove, pomegranate peel and grape seed extracts on Listeria monocytogenes, Staphylococcus aureus and Salmonella enterica were evaluated in raw pork at room temperature (～20 °C). The influences of these extracts on lipid oxidation in the meat were also investigated. The pH, colour parameters and TBARS (thiobarbituric acid‐reactive substances) values were tested periodically. The results showed that all five natural extracts, especially clove, were effective against the bacteria. During storage the colour parameters of the extract‐treated pork samples changed slightly, in comparison with significant changes in the control. Treatments with these extracts increased the stability of raw pork against lipid oxidation. Clove was the most effective for retarding lipid oxidation and presented the highest antioxidant activity in raw pork. CONCLUSION: This study suggests that the tested extracts, especially clove, have potential as natural preservatives to reduce numbers of pathogenic bacteria, colour degradation and lipid oxidation in raw pork. Copyright © 2009 Society of Chemical Industry     

Effects of ultra high hydrostatic pressure on Listeria monocytogenes and natural flora in broth, milk and fruit juices

Listeria monocytogenes was subjected to ultra high hydrostatic pressure (UHHP) treatments from 200 to 700 MPa at 25 °C in broth, raw milk, peach juice and orange juice. Survivor curves showed that cell death increased as pressure increased. After 10 min pressure treatment at 400 MPa reductions of about 2.09 and 2.76 log CFU mL^?1 in aerobic bacteria and L. monocytogenes, respectively, were produced in raw milk, this increased to 5.09 and 6.47 log CFU mL^?1, respectively, at 600 MPa. Death of bacteria at UHHP treatment was greater in orange juice than peach juice, and in peach juice than milk. Listeria monocytogenes was more sensitive to increased pressure than increased pressurization time. Injury of L. monocytogenes occurred from 0 to 100%. Factors effecting the rate of microbial inactivation are: pressure, age of cell, composition of medium, and pressurization time. UHHP inactivation can be used to extend shelf life and increase food quality during storage, and may also contribute to inactivation of L. monocytogenes.     

Antioxidant and antimicrobial activity and potential of heather (Erica spp.) extracts in the control of Listeria monocytogenes

In this work, heather and its flowers were studied regarding their antioxidant and antimicrobial activities. Plants were subjected to ultrasound-assisted methanolic extraction followed by fractionation. A phytochemical characterisation of extracts content in total phenols and flavonoids, and their antioxidant activity was performed. The antimicrobial activity was evaluated through the determination of minimum inhibitory concentration and by bioautography. Following, studies on the antilisterial potential were carried out by: time-kill curves, inhibition of biofilm formation and tolerance of Listeria monocytogenes to adverse conditions. The results evidenced the antioxidant activity in both extracts, as well as, the antimicrobial activity against Gram-positive bacteria. Concerning the evaluation of the antilisterial potential, a bacteriostatic behaviour and inhibition of biofilms formation ability were observed. Listeria monocytogenes showed an increased susceptibility to adverse conditions when preincubated with extracts. Thus, heather and its flowers may be a source of new compounds with antilisterial activity potential.