Improving the solid-phase extraction of “quat” pesticides from water samples

A novel strategy, based on the addition of a cationic surfactant, for preventing the interferences associated with a diminution in the efficacy of solid-phase extraction (SPE) with silica cartridges of diquat, paraquat and difenzoquat in water is developed. Conditions for extraction are optimised with respect to pH, cationic surfactant and its concentration. Humic acids, anionic surfactants, inorganic salts and other organic contaminants like pesticides, phenols, polycyclic aromatic hydrocarbons and polychlorinated biphenyls produce the studied interferences. The best performance is shown in the improvement of the "quats" recovery from waters with high levels of humic acids and anionic surf…

Nuts and dried fruits: Natural occurrence of emerging Fusarium mycotoxins

Abstract The occurrence of enniatins (ENs) and beauvericin (BEA) in nuts, dried fruits and dates available in Valencia (Spain) was surveyed in this study. To do this, seventy-four samples of nuts, dried fruits and dates were analyzed for the determination of mycotoxin contamination. Mycotoxins were identified and quantified using an ultrasonic-C18 extraction and LC–MS/MS with a triple quadrupole (QqQ) mass analyzer. The frequencies of contamination of nuts, shell, dried fruits and dates were 50%, 80%, 35.7% and 83.3%, respectively. Enniatin A (ENA) was the most predominant EN found in nuts (45.2%) while ENB was the most common EN found in dates (58.3%). The analytical results of the shell s…

Shelf life extension of mozzarella cheese contaminated with Penicillium spp. using the antifungal compound ɛ-polylysine.

Molds are one of the most important spoilage organisms on cheese which can lead to economic loss as well as raising public health concerns due to the production of mycotoxins. This study investigates the use of ɛ-polylysine as natural antimicrobial to inhibit fungal growth. The minimal inhibitory concentrations and minimal fungicidal concentrations of ɛ-polylysine were determined against Penicillium roqueforti, Penicillium nordicum, and Penicillium solitum. Then, polylysine was tested as surface antimicrobial for the preservation of mozzarella slice cheese inoculated with these Penicillium spp. and stored in plastic trays during 25 days. The minimal inhibitory concentrations calculated for…

Biopreservation of tomatoes using fermented media by lactic acid bacteria

Abstract Post-harvest spoilage fungi in tomatoes represent an economic loss for industry and consumers. There is currently an increasing demand for novel applications of bio-preservatives as replacers of chemical additives and pesticides in food. In this study, nine lactic acid bacteria strains isolated from tomato and sourdough were screened for antifungal activity in vitro against 33 fungal strains and used as bio-preservatives of tomato inoculated with Penicillium expansum and Aspergillus flavus. The identification of the compounds potentially responsible for the antifungal activity, such as organic acids, phenolic acids and volatile organic compounds (VOCs), were identified and quantifi…

Solid-phase extraction on C18 in the trace determination of selected polychlorinated biphenyls in milk.

The utility of solid-phase extraction with octadecylsilica for determining fifteen polychlorinated biphenyl (PCB) congeners from milk samples was examined. Recoveries higher than 80% and relative standard deviations better than 10% were obtained for PCBs from different kinds of milk (whole, skimmed, 2%, powdered, breast and evaporated). A comparison with other procedures was made. The described method provides better detection limits than those attainable with the liquid-liquid extractions currently used as standard methods, when capillary gas-liquid chromatography is used for the final determination. A study of the separation was also performed using six different fused-silica capillary co…

Mitigation of enniatins in edible fish tissues by thermal processes and identification of degradation products.

Emerging mycotoxins, such as enniatins and beauvericin, are common contaminants in vegetal matrices, but recently, the occurrence of mycotoxins in foodstuffs from animal origin has been also reported as they can be present in edible tissues of animals fed with contaminated feedstuffs. Sea bass, sea bream, Atlantic salmon and rainbow trout from aquaculture analyzed in the present survey showed contamination by emerging Fusarium mycotoxins enniatins (ENs). ENs were extracted from raw and cooked fish with acetonitrile and analyzed by Liquid Chromatography coupled to Mass Spectrometry. In this study, the stability of ENs was evaluated during food processing by the application of different cooki…

Presence of mycotoxins in Tunisian infant foods samples and subsequent risk assessment

Abstract A study on a set of cereal and cereal-based products (n = 117) intended for infant consumption was performed to determine the natural presence of twenty different mycotoxins by both liquid chromatography and gas chromatography coupled to tandem mass spectrometry (MS/MS). Analytical data showed that 67% of analyzed samples were contaminated by at least one mycotoxin at variable levels. Deoxynivalenol presented the highest incidence (38%) and reached a maximum level of 240 ng/g in a bsissa sample (oat product), higher than the maximum level set for DON in cereal products (200 ng/g). While, enniatin B was found in 25 samples with a maximum level of 316 ng/g found also in a bsissa samp…

Antifungal activity and shelf life extension of loaf bread produced with sourdough fermented by Lactobacillus strains

The objective of this study was to evaluate a water‐soluble extract from sourdoughs fermented with the lactic acid bacteria (LAB) for antifungal reflect on loaf bread. The extracts produced by Lactobacillus plantarum CECT 749 and L. bulgaricus CECT 4005 were effective against strains of Fusarium spp., Penicillium spp., and Aspergillus spp., with minimum inhibitory concentration ranging from 1.6 to 200 mg/ml and minimum fungicidal concentration from 1.6 to 400 mg/ml. LC‐ESI‐MS‐TOF was used to analyze the antimicrobial compounds. Several antimicrobial phenolic acids were found. Fermented sourdoughs used for the production of loaf bread produced a reduction of fungal growth in relation on the …

SOLID-PHASE EXTRACTION OF PESTICIDES FROM WATER SAMPLES

Detecting residues of urea and carbamate pesticides

Clean-up and confirmation procedures for gas chromatographic determination of pesticide residues in contaminated waters. Part I

The effects of sulphuric acid, potassium hydroxide and chromic acid on eleven organochlorine and ten organophosphorus pesticides were investigated. The treatments destroy some pesticides totally or partially, leave others unaltered and have a clean-up effect. These reactions can be used to confirm the presence of an identified pesticide. The clean-up extracts in the environmental samples facilitate the identification of the organochlorine and organophosphorus pesticides and their quantitative analysis. The results obtained for contaminated surface waters show the usefulness of these methods for multi-residue capillary gas chromatography without the need for other additional separative chrom…

Reaction of zearalenone and α-zearalenol with allyl isothiocyanate, characterization of reaction products, their bioaccessibility and bioavailability in vitro.

This study investigates the reduction of zearalenone (ZEA) and α-zearalenol (α-ZOL) on a solution model using allyl isothiocyanate (AITC) and also determines the bioaccessibility and bioavailability of the reaction products isolated and identified by MS-LIT. Mycotoxin reductions were dose-dependent, and ZEA levels decreased more than α-ZOL, ranging from 0.2 to 96.9% and 0 to 89.5% respectively, with no difference (p⩽0.05) between pH 4 and 7. Overall, simulated gastric bioaccessibility was higher than duodenal bioaccessibility for both mycotoxins and mycotoxin-AITC conjugates, with duodenal fractions representing ⩾63.5% of the original concentration. Simulated bioavailability of reaction pro…

Protective effect against mycotoxin occurrence of different additives in smoked fish

Comparison of gas and liquid chromatography coupled to mass spectrometry for the residue analysis of pesticides in organges

Liquid chromatography-mass spectrometry (LC-MS) with atmospheric pressure chemical ionization (APCI), and gas chromatography-mass spectrometry (GC-MS) with electron impact ionization (EI), are compared for the determination of eight pesticides in oranges. Seven of the selected pesticides, chlorpyriphos, chlorpyriphos-methyl, imazalil, α and β-endosulfan, endosulfan sulphate and dicofol, are commonly determined by GC whereas one, thiabendazole, can only be directly determined by LC. Primary ions [M-H]− or [M-Cl+O]− are obtained using LC-APCI-MS in negative ionization (NI) mode. In contrast, a high degree of fragmentation is reported with GC-MS. Both techniques were applied to oranges, which …

Occurrence, toxicity, bioaccessibility and mitigation strategies of beauvericin, a minor Fusarium mycotoxin.

Emerging Fusarium mycotoxins include the toxic secondary metabolites fusaproliferin, enniatins, beauvericin (BEA), and moniliform. BEA is produced by some entomo- and phytopathogenic Fusarium species and occurs naturally on corn and corn-based foods and feeds infected by Fusarium spp. BEA has shown various biological activities (antibacterial, antifungal, and insecticidal) and possesses toxic activity, including the induction of apoptosis, increase cytoplasmic calcium concentration and lead to DNA fragmentation in mammalian cell lines. Cereals food processing has an important effect on mycotoxin stability, leading to less-contaminated food compared to the raw materials. Different industrial…

Antimicrobial packaging based on ɛ-polylysine bioactive film for the control of mycotoxigenic fungi in vitro and in bread

Abstract ɛ‐Poly‐l‐lysine (ɛ‐PL) is a cationic peptide with a broad‐spectrum antimicrobial activity. This study investigates the use of ɛ‐PL as natural antimicrobial to inhibit fungal growth and to reduce aflatoxins (AFs) production. Antifungal activity of starch biofilms with different concentrations of ɛ‐Poly‐l‐lysine (ɛ‐PL) was determined in solid medium against Aspergillus parasiticus (AFs producer) and Penicillium expansum. Then, biofilms were tested as antimicrobial devices for the preservation of bread loaf inoculated with A. parasiticus CECT 2681 and P. expansum CECT 2278. Shelf life and AFs content were examined. Biofilms with concentrations of ɛ‐PL less than 1.6 mg/cm2 showed no fu…

Influence of probiotic microorganisms on aflatoxins B 1 and B 2 bioaccessibility evaluated with a simulated gastrointestinal digestion

Aflatoxins (AFs) are produced mainly by the molds Aspergillus flavus and Aspergillus parasiticus. Aflatoxin B1 (AFB1) is classified as carcinogenic to humans. The aim of this study was to evaluate the capacity of different strains of Lactobacilli (Lb.) and Bifidobacteria (Bf.) to reduce the bioaccessibility of AFB1 and aflatoxin B2 (AFB2), spiked in loaf bread, using a dynamic in vitro simulated gastrointestinal digestion system. Aliquots of 20 mL of gastric and duodenal fluids were sampled for the determination of the mycotoxins gastric and duodenal bioaccessibility respectively, by liquid-chromatography coupled to the mass spectrometry in tandem (LC–MS/MS). A reduction of AFs bioacc…

Dietary intake of nutrients of great interest in immunonutrition to prevent muscle damage in soccer players

Soccer is a sport in which players are exposed to long-term periods of training and players need to augment strength and fat-free massgains by resistance training, minimize muscle damage and soreness and help to improve endurance. Recently, the incidence of injuries hasincreased during and preceding soccer matches, which inuences the effectiveness of the team. One study

Analysis of Polychlorinated Biphenyls in Aqueous Samples Using C18 Glass Column Extraction

Abstract A method for polychlorinated biphenyl (PCB) trace extraction from contaminated water at the part-pertrillion levels is described. This procedure involves quantitative adsorption of PCBs on Cis glass microcolumns. PCBs are retained on the surface and subsequently eluted with n-hexane (5 mL) before gas chromatography. Recovery of water fortified with PCBs was 83.6-108.5%. Compared to liquid-liquid extraction methods, the Cis glass microcolumns give comparable results, lessen solvent costs, and are less time-consuming.

Enniatin B metabolites in liver and tissues of gilthead sea bream (Sparus aurata)

Mycotoxins presence in pre- and post-fermented silage from Tunisia

Abstract Silage represents a major part of the feed ration for livestock, being a potential cause of mycotoxicosis as it can be contaminated with toxigenic fungi capable of producing mycotoxins in suitable environmental conditions. In the present work, the presence of natural mycotoxins in samples collected of silage from the main producing areas in Tunisia (Ariana, Bizerte, Beja and Jendouba) was assessed based on different plant material (oat, barley, triticale, artichoke, sulla or raygrass). Mycotoxins were evaluated during three periods in green forage (P1) and subsequently in ensiled products after 60 days (P2) and 100 days (P3) of fermentation. Samples were extracted by a QuEChERS pro…

Whey fermented by using Lactobacillus plantarum strains: A promising approach to increase the shelf life of pita bread

Nowadays, there is an increasing concern regarding the shelf life of food products, leading producers to research natural antimicrobial agents to use in food preparation. In this study, we evaluated the antifungal activity of Lactobacillus plantarum fermented whey and then added the whey during preparation of pita bread to study shelf-life improvement. The fermented whey showed a satisfactory inhibitory (antifungal) effect against Penicillium expansum and Penicillium brevicompactum strains: the minimum inhibitory and minimum fungicidal concentrations ranged from 3.9 to 39.0 g/L and from 62.5 to 250 g/L, respectively. Addition of fermented whey increased the shelf life of the pita bread. Aft…

Beauvericin degradation during bread and beer making

Abstract Beauvericin (BEA) is a bioactive compound produced by the secondary metabolism of several Fusarium species and known to have various biological activities. This study investigated the degradation of the minor Fusarium mycotoxin BEA present at the concentration of 5 mg/kg in barley and wheat flour during beer and bread making. The influence of the making processes and of the formation of degradation products of BEA were evaluated during the beer and bread making. The concentration of BEA and its evolution during the production processes were determined with the technique of the liquid chromatography tandem mass spectrometry in tandem (LC-MS/MS), whereas the formation of the BEA degr…

INGENIERÍA GENÉTICA E INDUSTRIA AGROALIMENTARIA: VENTAJAS E INCONVENIENTES GENETIC ENGINEERING AND FOOD INDUSTRY: ADVANTAGES AND INCONVENIENCES EXEÑERÍA XENÉTICA E INDUSTRIA AGROALIMENTARIA: VENTAXAS EINCONVINTES

Abstract Resumen Resumo Nowadays biotechnology allows to perform accurate changes on the genetic material of organisms, being a very important tool in food industry. However just a few recombinant products can be found in the market, as a result of the social repulse against these kind of foods. According to the Community Normative, it is necessary to evaluate the safety for human being and environment security previous to introducing a recombinant food into the market. In this work, the recommended protocols for several organisms to attend this evaluation on a rational way are reviewed. These protocols are fundamentally based on the SAFEST elements (Safety Assessment of Food by Equivalence…

In vitro antifungal activity of bioactive peptides produced by Lactobacillus plantarum against Aspergillus parasiticus and Penicillium expansum

Abstract Food spoilage caused by mycotoxigenic moulds represents an important problem in food security. The antimicrobial peptides are compounds of natural origin constituted by a variable number (5–100) of amino acids held together through peptide bonds. In this work, the cell free supernatants (CFSs) containing peptides obtained from four strains of LAB were lyophilized, filtered and tested to determine the antifungal activity against Aspergillus Parasiticus and Penicillium expansum . CFS obtained by Lactobacillus plantarum showed the highest inhibition activity. CFS was fractionated by size exclusion chromatography and injected into the liquid chromatography coupled to diode array detect…

A natural strategy to improve the shelf life of the loaf bread against toxigenic fungi: The employment of fermented whey powder.

Whey powders are used as food ingredients in many applications, from bakery goods, soups and sauces to baby food. The objective of the study was to evaluate the antifungal property of a wheybased medium (WM) fermented by lactic acid bacteria. The antifungal activity of the WM was evaluated using antifungal tests on solid and liquid media. MIC and MFC ranged from 15.6 to 250 mg/ mL and 62.5 to 250 mg/mL, respectively. Using fermented WM for dough preparation produced a reduction of Penicillium expansum growth of 0.5–0.6 log CFU/g and an improvement in shelf life of 1–2 days in relation to control bread.

Development and validation of a liquid chromatography tandem mass spectrometry method for the analysis of beta-agonists in animal feed and drinking water.

A reproducible, sensitive and selective multiresidue analytical method for seven beta-agonists: clenbuterol (CBT), clenpenterol (CPT), ractopamine (RTP), brombuterol (BBT), mabuterol (MBT), mapenterol (MPT), and hydroxymethylclenbuterol (HMCBT) was developed and validated by using liquid chromatography tandem mass spectrometry (LC-MS/MS) in feed and drinking water samples. The validation was achieved according to the criteria laid down in the Commission Decision 2002/657/EC, however it was necessary to use minimum required performance limits (MRPLs) proposed by the Community Reference Laboratories (CRLs) due to the lack of maximum residue limits (MRLs) for beta-agonists. By setting up these…

Toxicity reduction of ochratoxin A by lactic acid bacteria.

Abstract Ochratoxin A (OTA) is a mycotoxin produced by the metabolism of fungus belonging to the genus Aspergillus and Penicillium. In this paper we report, the capacity of different cultures of lactic acid bacteria (LAB) to degrade OTA present in MRS broth at both pH 3.5 and 6.5. A study of OTA reduction during gastrointestinal digestion carried out with the LAB was also performed. Taking into account the two reduction mechanisms of OTA studied in this work as the enzymatic one and the adsorption on the cell wall, as well as at pH 3.5 and 6.5 the reduction values of OTA were in a range of 30–99%, being the strains with greater reduction (97% and 95%) Lb. rhamnosus CECT 278T and Lb. plantar…

Reduction of the enniatins A, A1, B, B1 by an in vitro degradation employing different strains of probiotic bacteria: Identification of degradation products by LC–MS–LIT

Abstract The degradation of the Fusarium mycotoxins ENs by 9 bacterial strains characteristic of the gastrointestinal tract like Bb. longum , Bb. bifidum , Bb. breve , Bb. adolescentes , Lb. rhamnosus , Lb. casei–casei , S. termofilus , Lb. ruminis , Lb. casei and twenty two strains of Saccharomyces cerevisiae was studied. The fermentations were carried out in the liquid medium of De Man Rogosa Sharpe (MRS) under anaerobic conditions for Bifidobacteria Streptococcus and Lactobacillus, and in Potato Dextrose Broth (PDB) for Saccharomyces strains, during 48 h. The degradation of the bioactive compounds ENs was also studied in a food system composed by wheat flour naturally contaminated by ENs…

Optimization of experimental conditions for the identification of pesticide mixtures on six GLC columns

Evaluation of biological and antimicrobial properties of freeze-dried whey fermented by different strains ofLactobacillus plantarum

The aim of this study was to evaluate the biological and antimicrobial activities of commercial freeze-dried whey fermented by lactic acid bacteria in order to valorize this high polluting liquid waste of the dairy industry. Freeze-dried whey was fermented by different strains of Lactobacillus plantarum (CECT 220, 221, 748) at three different times of fermentation (24, 48, 72 h). Afterwards, the extract was purified on centricon amicon with a cut-off of 3 kDa to obtain a permeate consisting of small bioactive compounds reported in the literature to show greater bioactivity. The purified and diluted samples were subjected to the biological and antimicrobial tests for the evaluation of antiox…

Antibacterial activity of the emerging Fusarium mycotoxins enniatins A, A1, A2, B, B1, and B4 on probiotic microorganisms

Abstract Enniatins (ENs) are secondary metabolites produced by several Fusarium strains, chemically characterized as N-methylated cyclohexadepsipeptides. These compounds are known to act as antifungal and antibacterial agents, but they also possess anti-insect and phytotoxic properties. In this study, the antimicrobial effect of pure fractions of the bioactive compounds ENs A, A 1 , A 2 , B, B 1 , and B 4 was tested towards nine probiotic microrganisms, twenty-two Saccharomyces cerevisiae strains and nine Bacillus subtilis strains. Antimicrobial analyses were carried out the disc-diffusion method using ENs concentrations ranging from 0.2 to 20,000 ng. Plates were incubated for 24 h at 37 °C…

Liquid chromatographic–mass spectrometric determination of post-harvest fungicides in citrus fruits

Liquid chromatography (LC)-atmospheric pressure ionisation (API)-mass spectrometry (MS) has been used to determine residues of five fungicides in oranges with a minimum sample cleanup. Atmospheric pressure chemical ionisation (APCI) and electrospray (ES) were compared and both gave similar results in terms of sensitivity and structural information. The main ions were [M+H]+ for carbendazim, imazalil, thiophanate methyl and thiabendazole, and [M+H-C4H9NHCO]+ for benomyl. Samples were extracted with sodium sulphate and ethyl acetate. Although benomyl and thiophanate methyl were transformed through the extraction procedure to carbendazim, the method showed good precision (13%) and recovery (70…

Hazard analysis and critical control points in deep-fat frying

The Hazard Analysis and Critical Control Point (HACCP) system was applied to sunflower oils used for frying in nineteen university restaurants. Guidelines for implementation that include training personnel, flow diagram, identifying hazards, controlling hazards at critical control points (CCP's), monitoring CCP's and measure of action for exceeding limit were developed. Polar compounds were used as a measure for deteriorated sunflower oil and the values obtained from university restaurants before and after personnel training and implementation of HACCP were determined. Implementation of the guidelines produced an improvement in the quality of the frying process, and all establishments reduc…

Evaluation of enniatins A, A1, B, B1 and beauvericin in Portuguese cereal-based foods

Sixty-one samples of Portuguese cereal-based foods were analysed for the occurrence of emerging mycotoxins called enniatins (A, A1, B and B1) and beauvericin. Samples were extracted with a mixture of acetonitrile/water (85/15, v/v) using an Ultra-Turrax homogeniser, and mycotoxins were detected with liquid chromatography coupled to a mass spectrometer. This method was validated and adequate values of recovery (70–103%) and relative standard deviation (<15%) were obtained. Signal suppression/enhancement was studied and matrix-matched calibration used to minimise this effect, but no additional clean-up step was necessary. The mass spectrometer was operated in selected reaction monitoring (…