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1.
The objective of this study was to investigate the inhibitory effect of Zataria multiflora boiss essential oils (ZEOs), ultraviolet (UV) radiation and their combination against Listeria monocytogenes biofilm in a simulated industrial model (SIM). The effect of minimal inhibitory concentration (MIC) and sub‐MIC concentration of ZEOs, different contact time of UV and their combination was evaluated in a SIM on 6‐ and 12‐day‐old L. monocytogenes biofilm. In a SIM, 0.3% ZEOs were adequate to completely eliminate 6‐ and 12‐day‐old biofilm grown on stainless steel coupons. The population of viable L. monocytogenes biofilm cells under a 15‐ to 45‐min contact time of UV treatment declined significantly at 6‐ and 12‐day‐old biofilm. The combined effect of ZEO and UV showed antagonist effects. These findings indicated that in the single use, ZEO and UV revealed a suitable antilisteria biofilm activity, while combining them is not a promising method to remove listeria biofilms from stainless steel surfaces.  相似文献   

2.
This study investigated the antibacterial mechanism of action of the seed essential oil of Eleutherococcus senticosus (ESEO) against foodborne pathogenic bacteria. Preliminarily, the ESEO (1000 μg disc?1) showed potential antibacterial effect as diameter of inhibition zones (12.0 ± 0.2–37.0 ± 2.0 mm) against the tested foodborne pathogens. The MIC and MBC values of ESEO against the tested bacteria were found in the range of 125–500 and 500–1000 μg mL?1, respectively. At MIC concentration, the ESEO had potential inhibitory effect on the cell viability of the tested pathogens. In addition, SEM analysis showed the inhibitory effect of ESEO as confirmed by considerable morphological alterations on the cell wall of B. cereus ATCC 13061 and E. coli O157:H7 ATCC 43889. Moreover, the ESEO revealed its mode of action against foodborne pathogens on membrane integrity as confirmed by release of extracellular ATP, 260‐nm absorbing materials and leakage of potassium ions. These findings confirm that the ESEO can be used as a potential antibacterial agent in food industry to inhibit the growth of various foodborne pathogens.  相似文献   

3.
A strain, Rahnella aquatilis L103, which was isolated from the soil around the roots of mushrooms, produced antibacterial protein though fermentation. This protein has broad antibacterial spectrum towards gram-positive and gram-negative bacteria. The protein has a significant antioxidant capacity on scavenging ABTS (82.5%, 120 μg mL−1), DPPH· (64.1%, 600 μg mL−1) and OH· (60.1%, 750 μg mL−1) as well. The protein was considered to be safe within concentration of 150 μg mL−1 as shown by MTT results and was applied to beef refrigerated preservation. The treatment group presented lower total viable counts (TVC), total volatile basic nitrogen (TVB-N), 2-thiobarbituric acid (TBA), meanwhile, higher sensory score and longer shelf life (2 days) compared with the control group (P < 0.05). The results indicated that the protein under safe concentration was beneficial to beef preservation.  相似文献   

4.
The antioxidant octyl gallate (OG) has been successfully grafted onto chitosan by means of horseradish peroxidase biocatalyst. The maximum gallate incorporation onto chitosan determined by 1H NMR spectroscopy was up to 16 molar%. The resulting materials displayed antioxidant capacities with DPPH radical inhibition percentage up to 23% upon the assay conditions. The grafting of the antioxidant on chitosan enhanced its antimicrobial activity. Minimal inhibitory concentration (MIC) for Escherichia coli was 0.5 g L?1. The native medium molecular weight chitosan alone or grafted with the lowest OG incorporation (ca. 11 molar%) attained 100% inhibition of E. coli, whereas lower inhibition was observed for all other materials 50.7–68.9% corresponding a reduction in the counts from 10.6 to 5.23–3.30 Log CFU mL?1. The inhibition of Listeria monocytogenes was significantly higher (59.8–100%) than that with the Gram negative bacterium reaching the MIC at 0.25 g L?1 with a reduction in the counts from 12.6 Log CFU mL?1 to 5.06–0 Log CFU mL?1.  相似文献   

5.
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  相似文献   

6.
A novel antimicrobial peptide named Pep39 has been isolated from anchovy hydrolysate using ÄKTA protein liquid chromatography and reverse‐phase high‐performance liquid chromatography. Its amino acid sequence was RLFRHAFKAVLRL with a molecular weight of 1626.92. Pep39 demonstrated antimicrobial ability against Escherichia coli ATCC 25922, Salmonella typhi ATCC 50013, Staphylococcus aureus ATCC 25923 and Bacillus subtilis ATCC 9372, with minimal inhibitory concentration (MIC) ranging from 4 to 32 μg mL?1. No cytotoxicity to mouse red blood cells was observed when its concentration was lower than 30 μg mL?1. Pep39 induced the influx of fluorescent probe 8‐Anilino‐1‐naphthalenesulfonic acid and the outflow of β‐galactosidase by increasing E. coli outer and inner membrane permeabilities, respectively. Flow cytometric analysis also demonstrated that Pep39 disrupted E. coli cell membrane. These results suggested that the antimicrobial mechanism of Pep39 involved cytoplasmic membrane damage.  相似文献   

7.
Low molecular mass (MM) chitosan with high degree of deacetylation (DDA) has excellent bioactivity including antioxidant, antibacterial and encapsulation properties. In this work, to reduce the MM of chitosan, microwave‐assisted heating treatment (MAHT) conditions were investigated using three factors at three levels Box‐Behnken design (BBD). Microwave heating (MH) time, H2O2 concentration and solid‐to‐liquid ratio significantly affected the DDA and MM of chitosan. The antibacterial activities of chitosan before and after degradation were investigated based on minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The results showed that a second‐order polynomial equation fitted the observed values using multiple regression analysis and had a high coefficient of determination (R2 = 0.9591 and 0.9161 for the DDA and MM of chitosan, respectively). An optimisation study was performed using Derringer's desirability function methodology, and the optimal conditions were 80‐s MH time, 1.5% H2O2 concentration and 1:40 solid‐to‐liquid ratio. The MIC and MBC of chitosan before and after degradation against Escherichia coli and Salmonella typhimurium were 0.031 and 0.063 mg mL?1, and 0.25 and 0.125 mg mL?1, respectively. The optimised DDA and MM of chitosan were 90.58 ± 2.04% and 124.25 ± 14.36 kDa, respectively, which significantly reduces the use of oxidant reagent.  相似文献   

8.
The present study evaluated the effects of carvacrol and thymol against Salmonella spp. biofilm on polypropylene. The efficacy of the compounds was assessed by quantifying Salmonella spp. cells during and after biofilm formation on polypropylene and performing scanning electron microscopy. During biofilm formation, carvacrol and thymol, at subinhibitory concentrations, reduced bacterial counts about 1–2 log, while established Salmonella spp. biofilms were reduced about 1–5 log by carvacrol and thymol, at MIC or 2× MIC. The greatest reduction in carvacrol‐treated biofilms, about 5 log, was observed with 156 and 312 μg mL?1 (MIC and 2× MIC) in established Salmonella Typhimurium ATCC 14028 biofilms. Thymol showed the greatest reduction, about 4 log, at 624 μg mL?1 (2× MIC) against mature Salmonella Enteritidis biofilm. Carvacrol and thymol reduced the number of Salmonella spp. cells on polypropylene, suggesting their potential for the control of Salmonella spp. biofilms.  相似文献   

9.
Shewanella putrefaciens is a marine bacterium and a major microbial cause of spoilage in low temperature stored seafood. A survey of fruits and culinary herbs was undertaken on Australian plants with high antioxidant capacities. Twenty‐eight extracts from thirteen plant species were investigated for the ability to inhibit S. putrefaciens growth. Of these, eight extracts (28.6%) substantially inhibited S. putrefaciens growth. The muntries (Kunzea pomifera), lemon aspen (Acronychia acidula) and desert lime (Citrus glauca) extracts were efficient anti‐S. putrefaciens agents, with MIC values ≤3000 μg mL?1. Of these, the muntries methanolic extract was the most potent growth inhibitor (MIC = 2240 μg mL?1). The aqueous desert lime extract was also an effective growth inhibitor (MIC of 3857 μg mL?1), whilst the methanolic bush tomato (Solanum aviculare), aqueous muntries and Davidson's plum (Davidsonia pruriens) extracts displayed moderate S. putrefaciens growth inhibition. All extracts were nontoxic in the Artemia fransiscana bioassay, with LC50 values (>1000 μg mL?1). Nontargeted HPLC‐QTOF mass spectroscopy (with screening against three compound databases) putatively identified twenty compounds that were present in both inhibitory muntries extracts. The low toxicity of these extracts and their inhibitory bioactivity against S. putrefaciens indicates their potential as natural fish and seafood preservatives.  相似文献   

10.
BACKGROUND: Chito‐oligosaccharide (COS) is generally known to possess many specific biological functions, especially antibacterial activity, depending on its size. To prepare a specific size range of COS, however, has proved difficult. The aim of this study was to establish a method for preparing a specific size range of antibacterially active COS by adjusting the degree of deacetylation (DD) of β‐chitosan in a Trichoderma harzianum chitinase‐hydrolysing process. RESULTS: The molecular weight spectrum, elucidated by viscosity‐average molecular weight, high‐performance liquid chromatography and thin layer chromatography, of COS in chitosan hydrolysate was significantly related to the DD of its original chitosan. Compared with the original form, COS produced at 90% DD showed superior activity against most Gram‐negative bacteria tested, with a minimum inhibition concentration (MIC) ranging from 55 ± 27 to 200 ± 122 µ g mL?1. Conversely, most Gram‐positive strains tested were less sensitive to COS (MIC > 880 ± 438 µ g mL?1) than to its original form. Among the Gram‐positive strains, Staphylococcus xylosus was the only exception in that it showed a high susceptibility to COS and had an MIC as low as 45 ± 11 µ g mL?1. CONCLUSION: The results indicate that the production of a specific size range of COS product is possible by altering the DD of chitosan in the chitinase‐catalysed process. To produce various sizes of COS for versatile biological functions, as seen in this study to inhibit various types of bacteria, is made possible in this established process. Copyright © 2008 Society of Chemical Industry  相似文献   

11.
The antimicrobial activities of anethole, anisic acid, and eugenol characterized from aniseed were tested against 18 organisms including both bacteria and yeasts. As far as their minimum inhibitory concentration (MIC) values were compared, they are nearly comparable but act in different ways. For example, anethole was noted to be effective against Saccharomyces cerevisiae with a minimum fungicidal concentration (MFC) of 200 µg mL?1 but the activity was observed only when this yeast was growing on fermentable carbon sources in a hypoxic condition. On the other hand, eugenol was effective against S. cerevisiae with an MFC of 800 µg mL?1 in any growing conditions. Anisic acid showed fungistatic activity against this yeast with an MIC of 400 µg mL?1, but not fungicidal up to 1600 µg mL?1. Copyright © 2007 Society of Chemical Industry  相似文献   

12.
Antimicrobial activities of high molecular weight water‐soluble chitosans (HMWWS) against selected Gram‐negative and Gram‐positive foodborne pathogens (initial inoculation of ca. 6.5 Log CFU mL?1) were evaluated. Chitosans with 789 kDa and/or 1017 kDa were dissolved in aspartic acid (AS) to obtain 1–4% w/v solutions. Among HMWWS, only 4% 789 kDa AS chitosan reduced E. coli counts by 2 Log CFU mL?1 from 7.33 at 0 h to 5.16 Log CFU mL?1 at 96 h, and they were not effective against S. Typhimurium. Depending on the concentrations, HMWWS completely inhibited V. cholerae, V. vulnificus and Vparahaemolyticus as well as B. cereus and L. monocytogenes after 48 h or 96 h of incubation. Compared with the control (no HMWWS), 2% or 3% 1017 kDa AS chitosans showed about 3 Log CFU mL?1 lower (4.72–4.86 vs. 7.71) for S. aureus at 96 h of incubation.  相似文献   

13.
R‐phycoerythrin (R‐PE) was purified from the red algae Bangia fusco‐purpurea after 35–50% ammonium sulphate fractionation followed by ion‐exchange column chromatography on DEAE‐Sepharose, resulting in a purity (A565/A280) ratio of 5.1. The circular dichroism spectroscopy results suggested that the structure of R‐PE is predominately helical. The antioxidant activity of R‐PE was studied and revealed changes in conformation and antioxidant activity at different temperatures and pH values. After in vitro‐simulated gastrointestinal (GI) digestion of R‐PE, the scavenging activity of ABTS radical (EC50, 769.9 μg mL?1), DPPH radical (EC50, 421.9 μg mL?1), hydroxyl radical (EC50, 32.4 μg mL?1) and reducing power (A700 = 0.5, 625.8 μg mL?1) were measured. Gel filtration chromatography analysis showed that the molecular weight distribution of the final GI digest that still contained high antioxidant activity was <3 kDa. Our present results indicate that digestion‐resistant antioxidant peptides of R‐PE may be obtained by in vitro GI proteinases degradation.  相似文献   

14.
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  相似文献   

15.
The aim of this study was to determine the chemical composition and the in vitro antimicrobial effects of seed essential oil of Ferulago angulata. The oil analyses by GC and GC/MS resulted in the identification of 39 compounds representing 91.07% of the oil. The major constituents were (Z)-β-ocimene (19.93%), α-pinene (15.50%), p-cymene (7.67%), sabinene (7.49%), β-phellandrene (5.5%), and α-phellandrene (4.95%). The oil was also screened for its antimicrobial properties against six bacteria (Erwinia amylovora, Xanthomonas oryzae, Pseudomonas syringae, Pectobacterium carotovorum, Ralstonia solanacearum, Bacillus thuringiensis) and six fungi (Alternaria alternata, Culvularia fallax, Macrophomina phaseolina, Fusarium oxysporum, Cytospora sacchari, Colletotrichum tricbellum). According to the results of antibacterial activity, B. thuringiensis (with 8 µL mL?1 minimal inhibitory concentration (MIC) and 15 µL mL?1 minimum bactericidal concentration (MBC)) was the most sensitive bacterium; P. carotovorum and R. solanacearum (with 20 µL mL?1 MIC and 30< MBC) were the most resistant bacteria. Additionally, a broad differentiation against all of the tested fungi showed that the most susceptible and resistant fungi after 6 days at the highest concentration (800 µL L?1) were F. oxysporum (100.0 ± 0.00%) and C. tricbellum (52.50 ± 1.67%) of growth inhibition, respectively.  相似文献   

16.
Three phytosterols were isolated from Musa spp. flowers for evaluating their capabilities in inhibiting glucosidase and amylase activities and glycation of protein and sugar. The three phytosterols were identified as β‐sitosterol (PS1), 31‐norcyclolaudenone (PS2) and (24R)‐4α, 14α, 4‐trimethyl‐5α‐cholesta‐8, 25(27)‐dien‐3β‐ol (PS3). IC50 values (the concentration of inhibiting 50% of enzyme activity) of PS1, PS2 and PS3 against α‐glucosidase were 283.67, 11.33 and 43.10 μg mL?1, respectively. For inhibition of α‐amylase, the IC50 values of PS1, PS2 and PS3 were 52.55, 76.25 and 532.02 μg mL?1, respectively. PS1 was an uncompetitive inhibitor against α‐amylase with Km at 5.51 μg mL?1, while PS2 and PS3 exhibited a mixed‐type inhibition with Km at 52.36 and 2.49 μg mL?1, respectively. PS1 and PS2 also significantly inhibited the formation of advanced glycation end products (AGEs) in a BSA–fructose model. The results suggest that banana flower could possess the capability in prevention of the diseases associated with abnormal blood sugar and AGEs levels, such as diabetes.  相似文献   

17.
In this study, the efficacy of ginger (Zingiber officinale Roscoe) essential oil (GEO) in reducing A. flavus growth and aflatoxin production was investigated. Gas chromatography coupled to mass spectrometry and nuclear magnetic resonance spectroscopy showed that the major components of GEO were α‐zingiberene (23.85%) and geranial (14.16%). Mycelial growth of Aspergillus flavus was reduced significantly at a GEO concentration of 150 μg mL?1, and complete inhibition of conidial germination was observed at a concentration of 10 μg mL?1. Statistically significant inhibition of ergosterol biosynthesis was detected at a GEO concentration of 10 μg mL?1. GEO was capable of fully inhibiting aflatoxin production by A. flavus at a concentration of 15 μg mL?1. The results suggest that low concentrations of GEO are capable of inhibiting aflatoxin production; such ability could be valuable in the upcoming future for agricultural companies to better control aflatoxigenic fungi in agricultural products.  相似文献   

18.
The in vitro inhibitory activities of different seed extracts prepared from cranberry bean mutant SA‐05 and its wild‐type variety Hwachia against aldose reductase, α‐glucosidase and α‐amylase were examined. The results indicated that the polyphenolics‐rich extracts obtained using 800 g kg?1 methanol and 500 g kg?1 ethanol demonstrated inhibitory activities against aldose reductase (IC50 of 0.36–0.46 mg mL?1) and α‐glucosidase (IC50 of 1.32–1.94 mg mL?1). The 500 g kg?1 ethanol extracts also showed α‐amylase inhibitory activities (IC50 of 70.11–80.22 μg mL?1). Subsequent extracts, prepared further with NaCl and H2O from precipitates of 800 g kg?1 methanol or 500 g kg?1 ethanol extracts, exhibited potent α‐amylase inhibitory activities (IC50 of 17.68–38.68 μg mL?1). A combination of 500 g kg?1 ethanol extraction plus a subsequent H2O extraction produced highest polyphenolics and α‐amylase inhibitors. The SA‐05 α‐amylase inhibitor extracts showed greater inhibitory activities than that of Hwachia. Thus, cranberry bean mutant SA‐05 is an advantageous choice for producing anti‐hyperglycaemic compounds.  相似文献   

19.
Comparative studies of functional properties among closely related mushroom species, supported by molecular identification, standard cultivation and extraction protocols, are not well documented. We compared antioxidant and antibacterial properties of standardised hydroalcoholic extracts of four Pleurotus species (P. levis, P. ostreatus, P. pulmonarius and P. tuber‐regium). Antioxidant properties were investigated using DPPH and ABTS radical scavenging capacity, total phenolic content, β‐carotene‐linoleic and ORAC assays. Antibacterial effect was assessed using the microplate method. The functional properties of standardised mushroom extracts were different in species studied. β‐carotene–linoleic acid and ORAC assays showed high antioxidant activity, particularly in P. ostreatus. Pleurotus tuber‐regium exhibited the lowest antioxidant activity in the ORAC assay (3316.0 μmol of trolox equivalent mL?1), but exerted the most potent bacteriostatic and bactericidal activity. Bacillus subtilis showed a high degree of susceptibility to a very low concentration (3.33 μg mL?1) of P. levis extract. Remarkable antioxidant and antibacterial properties were found in P. levis and P. tuber‐regium compared to the other species studied that are cultivated commercially.  相似文献   

20.
Three GRAS antimicrobials including, lauric arginate (LAE), bacteriophage P100 (phage P100) and bacteriocin nisin, were evaluated either singly or in combinations for the reduction of initial load of Listeria monocytogenes in cold‐smoked salmon (CSS). The stability of phage P100 in the presence of LAE (200 ppm) and nisin (500 ppm) or at 10× and 100× of these concentrations was determined at 4 °C or 30 °C for 24 h in a broth model. Phage P100 was found to be highly stable in the presence of these antimicrobial agents as plaque‐forming units (PFU) did not vary between control and antimicrobial‐treated phage. The survival of L. monocytogenes in the presence of phage P100, nisin and LAE showed remarkable reduction within 24 h both at 4 °C or 30 °C in broth. Treatment of CSS containing 3.5 log CFU cm?2 L. monocytogenes with phage P100 (10PFU mL?1), nisin (500 ppm) and LAE (200 ppm) showed strong listericidal action and reduced the L. monocytogenes by 2–3 log CFU cm?2 after 24 h. Among the combined treatments, phage P100 + LAE or nisin + LAE exhibited the most listericidal action in which L. monocytogenes cells were reduced to undetectable level within 24 h in CSS.  相似文献   

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