ABSTRACT
This brief report provides an overview of lessons learned through evaluation of the first five years of the NIA-funded South Carolina-Advancing Diversity in Aging Research (SC-ADAR) undergraduate program, whose goal is to increase the number of qualified underrepresented minority (URM) students who pursue scientific graduate studies in programs focusing on medicine, science, technology, engineering, and mathematics and aging. Partnering with five Historically Black Colleges and Universities in South Carolina, we implemented a research training approach that included two consecutive summers of research training in a University of South Carolina faculty laboratory, as part of a comprehensive 24-month research education program. In addition to the mentored research experience in a laboratory, students had coursework in the biology of aging and social gerontology, with additional workshops tailored to emergent student needs including basic academic skills development, work-life management skills, reflective social experiences, and enhanced support in the transition from undergraduate to graduate school. We provide an overview of lessons learned throughout the early program period, and a description of the iterative changes we made in the program in response to this learning, all of which have been incorporated into the existing SC-ADAR program.
Subject(s)
Geroscience , Minority Groups , Humans , Students , Mentors , AgingABSTRACT
In this study, liquid egg, albumen, and egg yolk were artificially inoculated with E. coli. Ultrasound equipment (20/40 kHz, 180/300 W; 30/45/60 min) with a circulation cooling system was used to lower the colony forming units (CFU) of E. coli samples. Frequency, absorbed power, energy dose, and duration of sonication showed a significant impact on E. coli with 0.5 log CFU/mL in albumen, 0.7 log CFU/mL in yolk and 0.5 log CFU/mL decrease at 40 kHz and 6.9 W absorbed power level. Significant linear correlation (p < 0.001) was observed between the energy dose of sonication and the decrease of E. coli. The results showed that sonication can be a useful tool as a supplementary method to reduce the number of microorganism in egg products. With near-infrared (NIR) spectra analysis we were able to detect the structural changes of the egg samples, due to ultrasonic treatment. Principal component analysis (PCA) showed that sonication can alter C-H, C-N, -OH and N-H bonds in egg. The aquagrams showed that sonication can alter the properties of H2O structure in egg products. The observed data showed that the absorbance of free water (1412 nm), water molecules with one (1440 nm), two (1462 nm), three (1472 nm) and four (1488 nm) hydrogen bonds, water solvation shell (1452 nm) and strongly bonded water (1512 nm) of the egg samples have been changed during ultrasonic treatment.
Subject(s)
Egg Yolk , Escherichia coli , Animals , Chickens , Colony Count, Microbial , Eggs , SonicationABSTRACT
Nigella sativa essential oil (EO) and its compounds (thymoquinone, carvacrol, and p-cymene) have a broad antimicrobial spectrum. The aim of this study was to investigate the antimicrobial and resistance modifying activity of N. sativa EO, thymoquinone, carvacrol, and p-cymene against one methicillin susceptible and one methicillin resistant Staphylococcus aureus strain. N. sativa EO, thymoquinone, carvacrol, and p-cymene were assessed for antimicrobial activity and modulation of antimicrobial resistance (by broth microdilution), inhibition of antimicrobial efflux (by ethidium bromide [EtBr] accumulation assay), relative expression of mepA gene (by real-time reverse transcriptase quantitative polymerase chain reaction), membrane disrupting effect (by LIVE/DEAD BacLight™ Kit), and finally antibiofilm activity (by the crystal violet assay). Both strains of S. aureus were susceptible to N. sativa EO, thymoquinone, and carvacrol. N. sativa EO and carvacrol induced the increase of EtBr accumulated by both S. aureus strains. Membrane integrity of ATCC strain was disrupted by carvacrol and p-cymene, whereas for the methicillin resistant S. aureus (MRSA) strain the membrane integrity was disrupted by each compound. N. sativa EO and its bioactive compounds such as carvacrol and p-cymene could be applied as resistance modifiers in MRSA strains.
Subject(s)
Anti-Bacterial Agents/pharmacology , Drug Resistance, Multiple, Bacterial/drug effects , Methicillin-Resistant Staphylococcus aureus/drug effects , Nigella sativa/chemistry , Oils, Volatile/pharmacology , Anti-Infective Agents/pharmacology , Benzoquinones/pharmacology , Biofilms/drug effects , Cymenes , Methicillin-Resistant Staphylococcus aureus/physiology , Microbial Sensitivity Tests , Monoterpenes/pharmacology , Plant Extracts/pharmacology , Staphylococcal Infections/drug therapy , Staphylococcal Infections/microbiology , Staphylococcus aureus/drug effects , Staphylococcus aureus/physiologyABSTRACT
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.
Subject(s)
Antibiosis , Lactobacillus plantarum/physiology , Listeria/physiology , Pediococcus/physiology , Hydrogen-Ion Concentration , Listeria/growth & development , Listeria monocytogenes/growth & development , Listeria monocytogenes/physiology , Osmotic Pressure , Stress, PhysiologicalABSTRACT
The spread of superbugs in dairy products can jeopardize global public health. To date, information on the incidence rates of virulent and ß-lactams-resistant (BLR) Salmonella in cheeses from rural areas of Egypt has been lacking. Biochemical, serological, antibiotic susceptibility, and multiplex PCR (M-PCR) tests were performed to identify and characterize Salmonella isolates. In this study, 44 (15.71%) Salmonella isolates of eight different serotypes were recovered from 280 samples of Rumi and pasteurized Kariesh cheeses across the Nile Delta region of Egypt. The most predominant serotypes were S. Typhimurium, S. Enteritidis, and S. Infantis. The virulence genes (invA, stn, and hilA) were identified in all isolates. However, spvC was only detected in S. Typhimurium. The highest resistance was developed against Erythromycin and Clindamycin (90.91%), followed by Ceftazidime and Cephalothin (84.09%). Meropenem and colistin were the most effective antibiotics. A high proportion (79.55%) of multi-drug resistance (MDR) isolates carried narrow spectrum (NS), extended-spectrum (ES), and AmpC-BLR genes. The blaOXA-1, blaOXA-2, blaTEM-1, blaCTX-M, blaCMY-1, and blaCMY-2 BLR genes were positive in 37.04%, 29.63%, 25.93%, 14.81%, 37.04%, and 3.70% of isolates, respectively. In conclusion, a high prevalence of virulence and BLR genes harboring Salmonella strains in Egyptian cheeses is considered a great threat to public health.
ABSTRACT
In order to intensify and guarantee the agricultural productivity and thereby to be able to feed the world's rapidly growing population, irrigation has become very important. In parallel, the limited water resources lead to an increase in usage of poorly characterized sources of water, which is directly linked to a higher prevalence of foodborne diseases. Therefore, analyzing the microorganisms or even the complete microbiome of irrigation water used for food production can prevent the growing numbers of such cases. In this study, we compared the efficacy of MALDI-TOF Mass spectrometry (MALDI TOF MS) identification to 16S rRNA gene Sanger sequencing of waterborne microorganisms. Furthermore, we analyzed the whole microbial community of irrigation water using high-throughput 16S rRNA gene amplicon sequencing. The identification results of MALDI-TOF MS and 16S rRNA gene Sanger sequencing were almost identical at species level (66.7%; 64.3%). Based on the applied cultivation techniques, Acinetobacter spp., Enterobacter spp., Pseudomonas spp., and Brevundimonas spp. were the most abundant cultivable genera. In addition, the uncultivable part of the microbiome was dominated by Proteobacteria followed by Actinobacteria, Bacteroidota, Patescibacteria, and Verrucomicrobiota. Our findings indicate that MALDI-TOF MS offers a fast, reliable identification method and can act as an alternative to 16S rRNA gene Sanger sequencing of isolates. Moreover, the results suggest that MALDI-TOF MS paired with 16S rRNA gene amplicon sequencing have the potential to support the routine monitoring of the microbiological quality of irrigation water.
ABSTRACT
Serratia marcescens strains from a dairy-producing environment were tested for their inhibitory effect on Listeria monocytogenes, Salmonella Hartford, Yersinia enterocolitica and Escherichia coli. Inhibition of foodborne pathogens was observed in the case of a non-pigmented Serratia strain, while the pigment-producing isolate was able to inhibit only Y. enterocolitica. The co-culturing study in tryptone soya broth (TSB) and milk showed that the growth of Salmonella was inhibited in the first 24 h, but later the pathogen could grow in the presence of the Serratia strain even if its cell concentration was 1000 times higher than that of Salmonella. However, we found that (1) concentrated cell-free supernatants had stronger inhibitory activity, which confirms the extracellular nature of the antagonistic compound(s). We proved that (2) protease and chitinase enzymes can take part in this mechanism, but they are not the main inhibitory compounds. The presence of prodigiosin was observed only in the case of the pigmented strain; thus, (3) we hypothesized that prodigiosin does not take part in the inhibition of the pathogens. However, (4) the combined effect of different extracellular metabolites might be attributed to the inhibitory property. Application of concentrated S. marcescens cell-free supernatant can be an effective antibacterial strategy in the food industry, mainly in the form of a bio-disinfectant on surfaces of food-processing areas.
ABSTRACT
In the downstream process, the bioconversion of lignocellulosic biomass can be improved by applying a biological pretreatment procedure using microorganisms to produce hydrolytic enzymes to modify the recalcitrant structure of lignocellulose. In this study, various Bacillus strains (B. subtilis B.01162 and B.01212, B. coagulans B.01123 and B.01139, B. cereus B.00076 and B.01718, B. licheniformis B.01223 and B.01231) were evaluated for the degrading capacity of wheat bran in the submerged medium using enzymatic activities, reducing sugars and weight loss as indicators. The obtained results revealed that the B. subtilis B.01162, B. coagulans B.01123 and B. cereus B.00076 could be promising degraders for the wheat bran pretreatment. Besides, the application of their consortium (the combination of 2-3 Bacillus species) showed the positive effects on cellulose bioconversion compared with monocultures. Among them, the mixture of B. subtilis B.01162 and B. coagulans B.01123 increased significantly the cellulase, endo-glucanase, and xylanase enzyme activity resulting in accelerating the lignocellulose degradation. Our results served a very good base for the development of microbial consortium for biological pretreatment of lignocellulosic raw materials.
Subject(s)
Bacillus , Cellulase , Biomass , Dietary Fiber , Hydrolysis , LigninABSTRACT
Pálinka is Hungarian traditional alcoholic drink, and its quality is strongly depending on applied yeast strain. Unfortunately, all commercial yeast strains used the production of pálinka are selected for oenological purpose, and thus the efficacy and aroma releasing capacity are vary depending on the type and quality of fruit used. In this study, the fermentation efficacy of nine commercial yeast strains of Saccharomyces cerevisiae was focused. All strains were able to do alcoholic fermentation of apple juice quite efficiently, and the simple sugars (fructose, glucose and sucrose) were almost exhausted at the end of fermentation. Meanwhile, the alcohol production capacity and yield were no significant differences (around 9.17 v/v %-9.43 v/v %), whereas the ability of sugar consumption of strains Uvaferm Danstil A and Fermicru AR2 was stronger than others. The differences in the concentration and composition of volatile compounds were recorded. The highest levels of total volatile compounds were observed in samples fermented with Uvaferm Danstil A, Fermiblanc Arom, Vin-O-Ferm Roses, and Fermicru AR2. Meanwhile total volatile compounds, 2-methyl-1-propanol, 3-methyl-1-butanol, total higher alcohols, ethyl acetate, and total esters were considered as key parameters for describing the profile of fermented apple juices, whereas total fusel alcohols, 2-methyl-1-propanol, 2-methyl-1-butanol, 3-methyl-1-butanol, and total volatile compounds were characteristic indicators of samples fermented with Uvaferm Danstil A. This work provides very good information of commercial yeast strains for industrial pálinka production.
Subject(s)
Malus , Volatile Organic Compounds , Wine , 1-Butanol , Butanols , Dietary Sugars , Ethanol/analysis , Fermentation , Fructose , Glucose , Malus/chemistry , Monosaccharides , Pentanols , Saccharomyces cerevisiae , Sucrose , Volatile Organic Compounds/analysis , Wine/analysisABSTRACT
Oligosaccharides especially prebiotics take high attention in the development of foods because of their physiological properties in human health. They are generally synthetized enzymatically via transferases or hydrolases from mold or bacteria. The fact is that such oligosaccharides synthetized by probiotic bacteria, should be utilized by these microorganisms. This study focused on the production of oligosaccharides with prebiotic potential by crude enzyme preparation from bifidobacteria. Both monosubstrates and bisubstrates systems together with TLC and HPLC techniques, were applied. The crude enzyme preparation has different hydrolase activities such as α-glucosidase (2U/mL), ß-glucosidase (0.3 U/mL), α-galactosidase (1.2 U/mL), ß-galactosidase (0.4 U/mL), ß-fructosidase (11.5 U/mL). Additionally, it also has transglycosylation activities on lactose, lactulose, maltose and sucrose substrates. Two or three types of oligosaccharides were detected. The glycosyltransferase activity peaked at 45 °C, pH 6.6 and 30 g/100 mL substrate concentration. Significant high amount of oligosaccharides were formed in the case of lactose:sucrose combination than others. Both glucooligosaccharides and galactooligosaccharides are detected in the reaction mixtures of bisubstrate. When the lactose is present, the galactosyltransferation is predominated. One-one new types of oligosaccharides were detected in the reaction mixture of bioconversion. Among newly synthetized oligosaccharides, the fraction namely OS4 was utilized by probiotic bifidobacteria only. In conclusion, new types of galacto- and glucooligosaccharides with high prebiotic potentials were synthetized by the crude enzyme from probiotic Bifidobacterium strains.
Subject(s)
Bifidobacterium , Prebiotics , Humans , Lactulose , Oligosaccharides , beta-GalactosidaseABSTRACT
Antibiotic resistance containment strategies at wastewater treatment plants need to be supported by a firm knowledge on the behavior of resistant bacteria within a diverse microbial population in the presence of trace amount of antibiotics. In this study via investigating the population dynamics of resistant/sensitive Staphylococcus aureus co-cultures in several model wastewater matrix systems, valuable insights were obtained into the effect of trace amount of antibiotics (piperacillin and erythromycin) on bacteria, and into the suitability of advanced oxidation treatment (electron beam irradiation) as a remediation measure. It appears that environmentally relevant concentration levels of the antibiotic present in a wastewater matrix leads to a shift in the population in favor of the sensitive subtype, presumably on account of triggering protective biochemical processes in the resistant mutant, which confer no selective advantage since the sensitive strain remains unaffected in this concentration range. The impact of these conditions on the population dynamics can be diminished by using advanced oxidation treatment, considering that degradation products from the wastewater matrix constituents (such as humic acid) might also have an effect. Furthermore, it became also apparent that the presence of trace amount of antibiotics while triggers biological processes in the resistant subtype, concomitantly makes the bacteria more sensitive towards the attack of free radicals during advanced oxidation treatment. The behavior of resistant bacteria under environmental conditions at the cellular and population level clearly merits more attention.
Subject(s)
Biochemical Phenomena , Wastewater , Anti-Bacterial Agents , Drug Resistance, Bacterial , Oxidation-Reduction , PiperacillinABSTRACT
Probiotic bacteria have been associated with a unique production of aroma compounds in fermented foods but rapid methods for discriminating between foods containing probiotic, moderately probiotic, or non-probiotic bacteria remain aloof. An electronic nose (e-nose) is a high-sensitivity instrument capable of non-invasive volatile measurements of foods. In our study, we applied the e-nose to differentiate probiotic, moderately probiotic, and non-probiotic Lactobacillus bacteria strains at different fermentation time points (0th, 4th, and 11th) of milk fermentation. The pH of the changing milk medium was monitored with their corresponding increase in microbial cell counts. An e-nose with two gas chromatographic columns was used to develop classification models for the different bacteria groups and time points and to monitor the formation of the aromatic compounds during the fermentation process. Results of the e-nose showed good classification accuracy of the different bacteria groups at the 0th (74.44% for column 1 and 82.78% for column 2), the 4th (89.44% for column 1 and 92.22% for column 2), and the 11th (81.67% for column 1 and 81.67% for column 2) hour of fermentation. The loading vectors of the classification models showed the importance of some specific aroma compounds formed during the fermentation. Results show that aroma monitoring of the fermentation process with the e-nose is a promising and reliable analytical method for the rapid classification of bacteria strains according to their probiotic activity and for the monitoring of aroma changes during the fermentation process.
ABSTRACT
Deliberate or accidental contamination of foods such as milk, soft drinks, and drinking water with infectious agents or toxins is a major concern to health authorities. There is a critical need to develop technologies that can rapidly and efficiently separate and concentrate biothreat agents from food matrices. A key limitation of current centrifugation and filtration technologies is that they are batch processes with extensive hands-on involvement and processing times. The objective of our studies was to evaluate the continuous flow centrifugation (CFC) technique for the rapid separation and concentration of bacterial spores from large volumes of milk. We determined the effectiveness of the CFC technology for concentrating approximately 10(3) bacterial spores in 3.7 liters (1 gal) of whole milk and skim milk, using Bacillus subtilis, Bacillus atrophaeus, and Clostridium sporogenes spores as surrogates for biothreat agents. The spores in the concentrated samples were enumerated by using standard plating techniques. Three independent experiments were performed at 10,000 rpm and 0.7 liters/min flow rate. The mean B. subtilis spore recoveries were 71.3 and 56.5% in skim and whole milk, respectively, and those for B. atrophaeus were 55 and 59.3% in skim and whole milk, respectively. In contrast, mean C. sporogenes spore recoveries were 88.2 and 78.6% in skim and whole milk, respectively. The successful use of CFC to concentrate these bacterial spores from 3.7 liters of milk in 10 min shows promise for rapidly concentrating other spores from large volumes of milk.
Subject(s)
Bacillus/isolation & purification , Centrifugation/methods , Clostridium/isolation & purification , Food Contamination/analysis , Milk/microbiology , Spores, Bacterial/isolation & purification , Animals , Colony Count, Microbial , Consumer Product Safety , Flow Injection Analysis , HumansABSTRACT
Listeria monocytogenes is a foodborne pathogen capable of employing stress adaptive responses to evade a variety of stressors including temperature stress. We employed two-dimensional gel electrophoresis coupled with matrix-assisted laser desorption/ionization-time of flight analysis to study the differential expression of L. monocytogenes (ATCC 43256) soluble proteins at heat shock (60 degrees C) conditions, prolonged heat shock (60 degrees C for 9 minutes) conditions, and thermotolerance-inducing (48 degrees C for 30 minutes followed by 60 degrees C for 9 minutes) conditions. We compared the proteome of L. monocytogenes under these conditions to the proteome at 37 degrees C. Eighteen proteins were differentially expressed at 60 degrees C (6 up-regulated and 12 down-regulated), 21 proteins were differentially expressed (12 up-regulated and 9 down-regulated) when the cells were exposed to 60 degrees C for 9 minutes, and 20 proteins were differentially expressed (10 up-regulated and 10 down-regulated) when cells were initially exposed to 48 degrees C for 30 minutes before 60 degrees C for 9 minutes. There was one unidentifiable protein with observed molecular weight of 50 kDa which was differentially expressed across the three temperature treatments. Thermotolerance-inducing conditions caused the up-regulation of a protein by as much as 12-fold. DnaN, a previously identified stress protein, was up-regulated almost threefold at 60 degrees C. TcsA, a lipoprotein (CD4 T cell-stimulating antigen), and Gap (glyceraldehyde-3-phosphate-dehydrogenase) were selectively expressed under prolonged heat shock conditions suggesting their potential as candidate marker proteins targets for identifying temperature-stressed L. monocytogenes cells.
Subject(s)
Bacterial Proteins/metabolism , Hot Temperature/adverse effects , Listeria monocytogenes/metabolism , Proteome/metabolism , Stress, Physiological , Down-Regulation , Electrophoresis, Gel, Two-Dimensional , Listeria monocytogenes/genetics , Proteomics/methods , Solubility , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Up-RegulationABSTRACT
The aim of this work was to investigate whether the agronomic traits of vermicompost prepared from partially stabilised sewage sludge digestate after thermophilic composting were more favourable than those of conventional compost. The effects of various additives (green waste, spent mushroom compost, wheat straw, biochar) were also tested after 1.5â¯months precomposting followed by 3â¯months vermicomposting with Eisenia fetida or by compost maturing. Vermicomposting did not result in significantly more intensive mineralisation than composting; the average organic carbon contents were 21.2 and 22.2% in vermicomposts and composts, respectively. Hence, the average total (N: 2.4%; P: 1.9%; K: 0.9%) and available (N: 160â¯mg/kg; P: 161â¯mg/kg; K: 0.8%) macronutrient concentrations were the same in both treatments. The processing method did not influence the organic matter quality (E4/E6) either. However, on average the concentration of the plant growth regulator kinetin was more than twice as high in vermicomposts.
Subject(s)
Agrochemicals/metabolism , Composting , Sewage , Agrochemicals/analysis , Animals , Oligochaeta/metabolism , Sewage/chemistryABSTRACT
Urogenital tract infection caused by obligate intracellular bacterium Chlamydia trachomatis D (CtrD) is a leading cause of sexually transmitted diseases. Essential oil (EO) of Nigella sativa has a broad antimicrobial spectrum. The aim of this study was to evaluate the antimicrobial activity of the bioactive compounds (p-cymene, thymoquinone, carvacrol, and thymol) of N. sativa EO against CtrD. The cytotoxic effects of the compounds were determined by MTT assay. In order to quantify the anti-chlamydial activity of the compounds, HeLa cells were infected with CtrD or CtrD treated previously with the compounds. The titer of the infectious CtrD was determined by indirect immunofluorescence assay. The minimum inhibitory concentrations of the compounds were evaluated by direct quantitative PCR. None of the compounds showed a cytotoxic effect on HeLa cells in the concentrations tested. According to the immunofluorescence assay, all of the compounds significantly inhibited the growth of CtrD. The quantitative PCR revealed that the minimum concentration that exerted anti-chlamydial activity was 3.12 µM in the case of thymoquinone and p-cymene, while that of carvacrol and thymol was 6.25 µM. Therefore, it can be concluded that bioactive compounds of N. sativa EO could be used as effective antimicrobial agents against CtrD.
ABSTRACT
BACKGROUND/AIM: N. sativa essential oil (EO) and its compounds (thymoquinone, carvacrol and p-cymene) have a broad antimicrobial spectrum. The aim of this study was to investigate the antimicrobial and resistance modifying activity of N. sativa EO, thymoquinone, carvacrol and p-cymene against Listeria monocytogenes. MATERIALS AND METHODS: N. sativa EO, thymoquinone, carvacrol and p-cymene was assessed for its antimicrobial activity, modulation of antimicrobial resistance, inhibition of antimicrobial efflux and membrane integrity by broth microdilution, ethidium bromide accumulation and LIVE/DEAD BacLight™ assays. RESULTS: L. monocytogenes showed substantial susceptibility toward N. sativa EO, thymoquinone, and carvacrol. A significant reduction in MIC's of EtBr and ciprofloxacin was noticed when tested in combination with N. sativa EO, thymoquinone, carvacrol and reserpine. In the presence of each compound the membrane integrity was disintegrated, and the EtBr accumulation increased which was comparable to positive control reserpine. CONCLUSION: N. sativa EO might have a potential for controlling the antibiotic resistance in Listeria.
Subject(s)
Drug Resistance, Bacterial/drug effects , Listeria monocytogenes/drug effects , Nigella sativa/chemistry , Plant Oils/pharmacology , Anti-Bacterial Agents/pharmacology , Benzoquinones/chemistry , Listeria monocytogenes/pathogenicity , Oils, Volatile/chemistry , Plant Oils/chemistryABSTRACT
Among Fusarium mycotoxins, deoxynivalenol (DON) is the most common contaminant in case of cereals and cereal-based foods in Hungary. In this study, Hungarian wheat (n = 305), maize (n = 108), wheat flour (n = 179) and pasta (n = 226) samples were analysed (N = 818). The samples were collected during 2008-2015 in Hungary. Applied methods of analysis were enzyme-linked immunosorbent assay and liquid-chromatography coupled with a mass spectrometer. Results were compared and evaluated with Hungarian weather data. Among cereal samples, in 2011, wheat was contaminated with DON (overall average ± standard deviation was 2159 ± 2818 µg kg-1), which was above the maximum limit (ML). In case of wheat flour and pasta, no average values above ML were found during 2008-2015, but higher DON contamination could be observed in 2011 as well (wheat flour: 537 ± 573 µg kg-1; pasta: 511 ± 175 µg kg-1).
Subject(s)
Flour/analysis , Food Contamination/analysis , Trichothecenes/chemistry , Triticum/chemistry , Zea mays/chemistry , Hungary , Time Factors , WeatherABSTRACT
Numerous studies have been published on the radiolysis of sulfonamide antibiotic solutions but little effort has been made to monitor the biological properties of degradation products. A complex approach should also clarify the changes in antibacterial activity and biodegradability, besides the usual screening of toxicity. To fill this gap, the ionizing radiation induced degradation of four sulfonamide antibiotics was investigated in dilute aqueous solutions, with emphasis on the biological assessment of decomposition products. Complete removal of sulfonamides was achieved by a low absorbed dose (1.5kGy). 2-2.5kGy dose was needed to transform the persistent initial molecules to substances biodegradable in both river water and activated sludge. The ratio of the biological and chemical oxygen demand increased from <0.21 to at least 0.59, but values as high as 0.80 were also measured. It was demonstrated that antibacterial activity is due to the initial molecules, as it disappeared when the sulfamethoxazole concentration decreased below the minimal inhibitory concentration (30 µM). This means that the products have no antibacterial activity. Toxicity testing performed on test organisms from three different trophic levels and activated sludge evidenced that the toxicity depends both on the test organism and on the sulfonamide used. The degradation of initial molecules is not always enough to eliminate the environmental risk due to the toxic products formed e.g. inhibitory effects to Vibrio fischeri increased by 34% at 2.5kGy. For this reason, complex biological assessment of treated solutions has to play an important role in development and optimization of advanced treatment techniques.
Subject(s)
Anti-Bacterial Agents/chemistry , Sulfonamides/chemistry , Water Pollutants, Chemical/chemistry , Aliivibrio fischeri/drug effects , Anti-Bacterial Agents/toxicity , Biodegradation, Environmental , Sulfonamides/toxicity , Toxicity Tests , Waste Disposal, Fluid/methods , Water Pollutants, Chemical/toxicityABSTRACT
The Fusarium mycotoxins deoxynivalenol (DON), zearalenone (ZEN) and T-2 frequently contaminate grain crops in Middle and Eastern Europe. In this survey, 116 cereal samples (maize, wheat, barley and oat) were examined for DON, ZEN and T-2 mycotoxins. Samples were collected from different areas in two Hungarian regions (North and South Transdanubia). The method of analysis was indirect competitive ELISA. Maize was the most contaminated grain regarding DON (86%), ZEN (41%) and T-2 (55%) toxins. The average results of the deoxynivalenol and zearalenone tests of maize proved to be significantly higher than those of barley or oat. DON was the most represented Fusarium mycotoxin followed by T-2 and ZEN. The examination of these mycotoxins would be necessary at a larger scale as to re-evaluate permissible levels, so increase of the monitoring programme would be advisable for the future.