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The issue of food and feed contamination by fungi and aflatoxins constitutes a signficant issue for human and animal health, agriculture, and the economy. Aflatoxin B1 (AFB1) is considered to be th...

The issue of food contamination by fungi and aflatoxins; constitutes a serious concern not only for human/animal health but also for agriculture and the economy. Aflatoxins are secondary metabolites produced by certain filamentous fungi and contaminate a variety of foodstuffs. In this context, control of fungal growth and aflatoxin contamination appears to be important. The present study aimed to investigate new Cu(I) and Cu(II)–quinoxaline complexes, namely [Cu(2,2´-pq)(NO3)](NO3) (1), [Cu(2,2´-pq)2(NO3)](NO3)·6H2O (2) and [Cu(2,2΄-pq)2](BF4) (3), where 2,2´-pq is 2-(2’-pyridyl quinoxaline), as antifungal agents against Aspergillus parasiticus. All complexes, the ligand and the starting material Cu(NO3)2–3H2O, regardless of the concentration used, caused inhibition of A. parasiticus growth ranged from 8.52 to 33.33%. The fungal growth inhibition was triggered when irradiation in visible (λ > 400 nm) was continuously applied (range 18.36–57.20%). The highest inhibitory activity was exhibited by the complex [Cu(2,2´-pq)2(NO3)](NO3)·6H2O and for this reason, it was selected to be studied for its ability to suppress aflatoxin B1 produced by A. parasiticus. AFB1 production after the irradiation process was found to be suppressed by 25% compared to AFB1 produced in dark conditions.

Food decay by spoilage fungi leads to significant economic losses and hazards to consumers' health due to the potential of mycotoxin occurrence. Ochratoxin A (OTA) is a mycotoxin known as nephrotoxic and carcinogenic to humans. Natural capsaicin was evaluated for its effectiveness against the growth of five Aspergillus section Nigri strains and accumulation of OTA in inoculated black grapes. Results showed that capsaicin was effective in inhibiting fungal growth and OTA production by new four Aspergillus section Nigri strains (ATHUM 6997, 6998, 6999, 7000) and by Aspergillus carbonarius as well. Moreover, capsaicin addition exhibited maximum inhibition of OTA produced by ATHUM 6997, 6998, 6999, and 7000 in black grapes at 28.9%, 8.6%, 68.4%, and 78.1%, respectively. Inhibition percentage of OTA production by A. carbonarius in grapes treated with capsaicin was estimated at 61.5%. These results suggest that capsaicin influences the OTA biosynthesis pathway of all Aspergillus section Nigri strains and therefore could be used as an effective natural preservative against OTA contamination of vineyards. Risk assessment revealed that when grapes are treated with capsaicin, consumers are less exposed to OTA.

Aflatoxins are secondary metabolites, with aflatoxin B1 being the most common, reported as carcinogenic, teratogenic and genotoxic. This study investigates the antiaflatoxigenic efficacy of the herbaceous plant Cistus incanus L. against Aspergillus parasiticus in two substrates, yeast extract sucrose medium and macadamia nuts. The methanolic extract of Cistus incanus showed pronounced antiaflatoxigenic ability, inhibiting aflatoxin B1 production in both substrates. AFB1 production was decreased significantly in a percentage of 87.1–90.1% after Cistus incanus extract addition in YES medium. The extract effectiveness was also observed in macadamia nuts, where the AFB1 production by Aspergillus parasiticus was reduced in a percentage of 72.5–85.9%. Moreover, the risk assessment was estimated taking into account the maximum amounts of AFB1 produced in inoculated samples with and without Cistus incanus addition. It was revealed that Cistus incanus presence leads to a lesser exposure of AFB1 to consumers.

Antioxidant activities and phenolic contents of selected superfoods and superherbs, cultivated in regions of Greece, were investigated so as to supply new information on their antioxidant function. The total antioxidant capacity was estimated by DPPH• (1,1-diphenyl-2-picrylhydrazyl radical) assay while total phenolics were measured using Folin–Ciocalteu method. Moreover this study was carried out with a supplementary objective to investigate the antifungal activities of the selected superfoods/superherbs extracts. The in vitro antifungal assays were done against the mycotoxigenic fungus Aspergillus parasiticus (aflatoxigenic) and Aspergillus carbonarius (ochratoxigenic). The results showed diversity on antioxidant profile of the studied extracts, although in most of the cases, the analysis revealed significant antioxidant capacity and high total phenolic content. Specifically, Photinia melanocarpa L., Hippophae rhamnoides L. leaves, Cistus incanus L., and Crataegus monogyna Jacq., possessed the highest antioxidant capacities and total phenolic contents among the others. Moreover, most of the tested extracts inhibited the growth of A.parasiticus and A.carbonarius while some of them stimulated the fungal growth, for both of the mycotoxigenic fungi. Tribulus terrestris and Cistus incanus proved to be more effective in reducing the growth of the tested fungi while Vaccinium corymbosum (blueberries) had stimulating effect on the fungi’s growth.

Aflatoxin B1 has been considered as the most potent liver carcinogen for humans. One factor that stimulates the production of aflatoxins in oilseed products, such as sesame seeds and their products is the presence of high levels of fatty acids. This work presents further evidence that sesame is a favorable substrate for aflatoxin B1 production by Aspergillus parasiticus. Moreover, the use of wild artichoke (Cynara cardunculus L.) extract was examined showing inhibition of aflatoxin B1 production in both sesame and yeast extract sucrose medium, inoculated with A. parasiticus. More specifically, the inhibition of aflatoxin B1 production by A. parasiticus in sesame seeds paste was 99.6% and in yeast extract sucrose medium it was 99.4%.

Ochratoxin A (OTA) is a mycotoxin of great interest to humans for its nephrotoxic effects. The development and validation of an OTA method determination in raisins is described by using High Pressure Liquid Chromatography (HPLC) with Fluorescence Detector (FD). The recovery of the method was 104% while the detection limit (DL) and quantification limit were 0.26 and 0.51 ng g −1 , respectively. The effect of gamma irradiation at dose of 10 kGy on the production of OTA by Aspergillus carbonarius in raisins ( Vitis vinifera L.) and on OTA in contaminated samples, was investigated. The OTA which was produced by A. carbonarius on the 12th day of incubation, after irradiation, showed that at dose level of 10 kGy, OTA production was not detectable (below the detection limit of the method) compared with the non-irradiated the same day. A dose of 10-kGy gamma radiation applied on 100 ng of OTA , in raisins reduced OTA contamination ~88%. According to the risk assessment analysis the Provisional Maximum Tolerable Daily Intake (PMTDI) of 5.8 ng OTA kg −1 bw, indicates that adult consumers are less exposed, 31.4–78.4 fold lower to OTA by the irradiated raisins.

The ability of Listeria monocytogenes to adapt to low temperature, low pH, and osmotic stress, to withstand cleaning and disinfection agents, to induce stress-related cross-protection responses, and to form biofilms, enables it to prevail and survive most of the common safety measures employed in industrial-scale food processing to ensure food safety. The objective of this study was to determine the changes that occur in the lipid composition of the membrane of L. monocytogenes under the conditions of the manufacture and storage of a laboratory-prepared soft cheese (feta type). The results show that L. monocytogenes cells present in the raw milk may survive the cheese manufacturing process as well as the storage period and that the history of the inoculated cells has an effect on their behavior during storage of the cheese. The bacterium seems to follow different pathways and adopt different strategies to preserve the optimal fluidity and functions of the membrane depending on the length of storage time and the history of the inoculated cells. In this context, cells derived from pre-inoculated cells grown in optimal or acidic conditions showed an increase in the number of straight chain fatty acids (SCFA) relative to branched ones (BCFA), without altering the ratio of BCFA C15:0 to BCFA C17:0 and the ratio of iso to anteiso FA. Alternatively, those cells derived from pre-inoculated cells grown in presence of benzalkonium chloride followed a different pathway. These cells achieved a balance between optimal fluidity and solid phase membrane not only by changes in SCFA content, but also by changes in the ratios of BCFA C15:0 to C17:0 and of iso to anteiso fatty acids. This latter approach to maintain membrane fluidity seems to be paired with the different survival trends of the bacterium under the conditions of this study.

Aflatoxin B 1 (AFB 1 ) mostly produced by Aspergillus flavus and Aspergillus parasiticus , is an extremely toxic and carcinogenic metabolite. The effect of gamma irradiation at dose of 10 kGy on the production of aflatoxin B 1 (AFB 1 ) inoculated by Aspergillus parasiticus in raisins ( Vitis vinifera L.) and on AFB 1 in contaminated samples, was investigated. Values of the amount of aflatoxin B 1 produced on the 12th day of incubation, after irradiation, showed that gamma radiation exposure at 10 kGy decreased AFB 1 production at 65% compared with the non-irradiated sample, on the same day. The application of 10 kGy gamma radiation directly on 100 ng of AFB 1 which were spiked in raisins resulted in ~29% reduction of AFB 1 . According to the risk assessment analysis the Provisional Maximum Tolerable Daily Intake (PMTDI) of 1.0 ng AFB 1 kg −1 bw, indicates that consumers are less exposed to AFB 1 from the irradiated raisins.

Aflatoxin B1 (AFB1) mostly produced by Aspergillus flavus and Aspergillus parasiticus, is an extremely toxic and carcinogenic metabolite. Currants are used in the Mediterranean diet as a food with antioxidant properties. Four strains of Aspergillus section Nigri have been isolated from currants originated from Crete and Corinth. In this study AFB1 production by A. parasiticus and the four strains of Aspergillus section Nigri in Cretan and Corinthian currants (Vitis vinifera L.) is investigated. AFB1 determination was performed by HPLC–FID. Results revealed that the four strains Aspergillus section Nigri, as well as the aflatoxigenic strain A. parasiticus produced AFB1 (0.0052–1.31 μg AFB1 15 g−1, corresponding to 0.0003–0.087 μg AFB1 g−1) in both type of currants (Cretan and Corinthian) on the 12th day of observation. Moreover, AFB1 production, by A. parasiticus in the synthetic Yeast Extract Sucrose (YES) medium was also studied. The ability of AFB1 production has been affected by the special characteristics of each isolate and the currants substrate.

Twenty-six samples of dried vine fruits from Athens and Thebes (Central Greece) market were simultaneously extracted and cleaned up by immunoaffinity columns and analysed for aflatoxin B1 (AFB1) and ochratoxin A (OTA). A combination of ELISA and HPLC methods was applied for the determination of AFB1. Recovery was 97.6%, RSD 6.46%, while the limit of detection (LOD) and limit of quantification (LOQ) were 0.05 μg kg(-1) and 0.09 μg kg(-1), respectively. OTA concentrations were only estimated by ELISA. Results revealed the presence of AFB1 in 23% of the samples (mean 1.4 μg AFB1 kg(-1)), but none exceeded the EU limit (2 μg AFB1 kg(-1)). However, OTA was detected in 100% of the samples (mean 47.2 μg OTA kg(-1)). Six samples were found to be contaminated at high levels (median 120.6 μg OTA kg(-1)) and 18 exceeded the EU limit (10 μg OTA kg(-1)).

Aflatoxin B1 (AFB1) is considered as the most potent liver carcinogen for humans. A method for determination in sesame seeds was developed. AFB1 was extracted by methanol-water, cleaned by immunoaffinity columns and determined by high-performance liquid chromatography with fluorescence detection. The recovery factor and the limit of detection (LOD) of AFB1 in sesame seeds were 111.5% and 0.02 ng g−1, respectively. Thirty samples of sesame products were examined for the presence of AFB1. After analysis, 77.6% of samples were found to be contaminated. Eight samples exceeded the European Union (EU) limit (2 µg AFB1 kg−1). In 15 samples, AFB1 was below the EU limit. Seven samples remained below the LOD. The most contaminated (14.49 ng AFB1 g−1) sample was unpeeled packaged sesame seeds. In all samples, aflatoxigenic Aspergilli fungi as well as the risk for AFB1 presence in sesame seed was investigated.

Extracts of different parts (heads, bracts and stems) of Cynara cardunculus L. (cardoon) and Cynara scolymus L. (globe artichoke), obtained by two different extraction techniques (Ultrasound-Assisted Extraction (UAE) and classical extraction (CE)) were examined and compared for their total phenolic content (TPC) and their antioxidant activity. Moreover, infusions of the plant’s parts were also analysed and compared to aforementioned samples. Results showed that cardoon’s heads extract (obtained by Ultrasound-Assisted Extraction) displayed the highest TPC values (1.57 mg Gallic Acid Equivalents (GAE) g−1 fresh weight (fw)), the highest DPPH• scavenging activity (IC50; 0.91 mg ml−1) and the highest ABTS•+ radical scavenging capacity (2.08 mg Trolox Equivalents (TE) g−1 fw) compared to infusions and other extracts studied. Moreover, Ultrasound-Assisted Extraction technique proved to be more appropriate and effective for the extraction of antiradical and phenolic compounds.

Aflatoxin B1 (AFB1) is a carcinogenic metabolite produced by certain Aspergillus species. The aim of the present study was to investigate the effect of saffron stigmas on A. parasiticus growth and AFB1 production in Yeast Extract Sucrose (YES) medium. AFB1 was extracted from cultures and purified with immunoaffinity columns followed by high performance liquid chromatography (HPLC) coupled to fluorescence detector (FL) analysis. Methods' recovery and limit of detection were 95.3% and 0.02 ng AFB1·ml–1 of YES respectively. Results indicated that AFB1 production in samples of YES inoculated with A. parasiticus after the addition of saffron dried stigmas (100 mg·flask–1) was significantly lower (p < 0.05) compared to control samples (inoculated without the addition of saffron stigmas) throughout the entire incubation period (18 days), at the same time as mycelial growth was noticeable. In addition, mycelial growth was observed and AFB1 was detected, after the 7th day of observation in cultures with saffron alone. Maximum production was observed on the 12th day (0.018 μg AFB1·flask–1) and on the 9th day (0.051 μg AFB1·flask–1) for samples of YES with the addition of saffron inoculated with A. parasiticus and samples with saffron alone (non-inoculated), respectively. In control samples (inoculated without saffron) the maximum production on the same days 12 and 9 was 75.31 μg AFB1·flask–1 and 64 μg AFB1·flask–1 respectively. Conclusively when saffron was added to YES inoculated with A. parasiticus, AFB1 production decreased by 99.9% compared to control cultures without saffron addition. This inhibition can be attributed to the antioxidant capacity of saffron constituents.

Aflatoxin B1 (AFB1) is a carcinogenic metabolite produced by certain Aspergillus species such as A. parasiticus and A. flavus. The beneficial properties of bee pollen have transformed this commodity into an increasingly frequent component of the human diet. As bee pollen is a substrate on which aflatoxigenic fungi can grow, AFB1 production is likely. In the present study, we describe a method for aflatoxin B1 determination in bee pollen utilising high pressure liquid chromatography (HPLC) with a fluorescence detector (FD). The recovery factor of the method was found to be 111% (RSD% 1.61), while the detection limit (LOD) was 0.08 ng AFB1/g. An additional aim of this study was to investigate the growth of A. parasiticus and AFB1 production in bee pollen. Results indicated that no mycelial growth was observed and no AFB1 was detected in bee pollen samples containing natural microbiota throughout the entire observation period (20 days). In contrast, AFB1 production in treated bee pollen samples (15 g pollen/flask) inoculated with A. parasiticus was significantly higher (p ≤ 0.05) compared to control samples (treated but not inoculated) throughout the entire incubation period, while no mycelial growth was apparent. Maximum production was observed on the 12th day (79.29 ng AFB1/flask and 32.44 ng AFB1/flask for inoculated and non-inoculated bee pollen, respectively). As a result, AFB1 production in bee pollen is likely even following a minor contamination, which could occur randomly.

A method for aflatoxin B1 (AFB1) and ochratoxin A (OTA) determination in breakfast cereals is described using a simultaneous methanolic-aqueous extraction followed by immunoaffinity columns clean-up step and High Pressure Liquid Chromatography (HPLC) with Fluorescence Detector (FD). Recoveries were found to be 78% and 83% for AFB1 and OTA, respectively, while the detection limit (DL) was 0.02 ng g−1 for both mycotoxins. Both determinations were applied in fifty five samples of breakfast cereals purchased from Athens market. Results revealed the presence of AFB1 in 56.3% of the samples examined (mean 1.42 ng AFB1 g−1). Seven samples (median 3.5 ng AFB1 g−1) were found to be contaminated at levels higher than the EU limit (2 g g−1). OTA was detected in 60% of the samples (mean 0.18 ng g−1). Nineteen samples were found to be contaminated by both mycotoxins. In addition in the present study the daily exposure to AFB1 and OTA is discussed.

AflatoxinB1(AFB1) is a carcinogenic metabolite produced by certainAspergillusspecies on agricultural commodities. AFB1biosynthesis is affected by jasmonic acid and also by its methylester (MeJA), a plant growth regulator derived from linoleic acid. This study reports the effect of MeJA on the growth ofA. parasiticusand AFB1output in yeast extract sucrose (YES) medium when added at three different concentrations; namely,10−2 M,10−4 M, and10−6 M. AFB1determination was performed by immunoaffinity and HPLC. MeJA at10−4and10−6M concentrations had no significant effect on mycelial growth but did affect AFB1production after the 7th day of incubation; on the 12th day, AFB1production was increased by 212.7% and 141.6% compared to the control samples (addition of10−6 M and10−4 M MeJA, resp.). Treatment ofA. parasiticuscultures with10−2 M MeJA inhibited mycelial growth and AFB1production as well. These results suggest that the effect of MeJA on AFB1biosynthesis byA. parasiticusdepends on the MeJA concentration used.

A high performance liquid chromatography with a diode-array detector (HPLC-DAD) and a gas chromatography with a mass spectrometer (GC-MSD) are described for the determination of patulin (PAT) in apple juice. The limits of detection (DL) and quantification (QL) for the HPLC-DAD and GC-MSD method were found to be (DL=0.23μgkg(-1) QL=1.2μgkg(-1)) and (DL=5.8μgkg(-1) and QL=13.8μgkg(-1)), respectively. The recovery factors for HPLC-DAD and GC-MSD were found to be 99.5% (RSD%=0.73) and 41% (RSD%=10.03), respectively. The HPLC-DAD method was used to determine the occurrence of PAT in 90 samples of fruit juices. Results revealed the presence of PAT in 100% of the samples examined. The mean values of PAT in concentrated fruit juices and in the commercial fruit juices collected from the Greek market were found to be 10.54μg PAT kg(-1) and 5.57μg PAT kg(-1) juice, respectively. The most contaminated samples were four concentrated juices ranging from 18.10μg PAT kg(-1) to 36.8μg PAT kg(-1) juice. The daily exposure to patulin for the consumers of all ages in Greece, is ranging from 0.008μg PAT kg(-1) bw to 0.1μg PAT kg(-1) bw if the daily intake of fruit juices is from 0.1 to 0.5kg. With the exception to the most contaminated sample, the daily exposure due to the samples examined, is below the provisional maximum tolerable daily intake for PAT (0.4μg PAT kg(-1) bw).

Aflatoxin B 1 (AFB 1 ) is a carcinogenic metabolite produced by certain Aspergillus species. Ochratoxin A (OTA) is a metabolite of Aspergillus ochraceus and Penicillium verrucosum . AFB 1 and OTA are amongst the most frequent combinations of mycotoxins found in plant products. Thus, synergistic effects or interactions between the two mycotoxins could be taking place. The aim of the present study was to investigate the effect of OTA on Aspergillus parasiticus growth and AFB 1 production in yeast extract sucrose (YES) medium at concentrations of 0.16, 1.6 and 16 ng OTA flask −1 . The AFB 1 extracted from cultures and purified with immunoaffinity columns was then quantitated by HPLC. The recovery and detection limit of the method were 95.3% and 0.02 ng AFB 1 mL −1 , respectively. Maximum AFB 1 productions in cultures with OTA were observed from 9 to 12 days (76.09–82.52 ng AFB 1 flask −1 ) while in control cultures (without OTA) maximum production (197.2 ng AFB 1 flask −1 ) was observed on 14th day. Maximum AFB 1 levels in cultures with OTA were reduced by a percentage of 58–61% compared to control cultures. Furthermore AFB 1 levels in cultures with OTA were practically (92%) degraded after 18 days of incubation. Conclusively when OTA is present the production of AFB 1 by A. parasiticus in YES medium is inhibited.

Aflatoxin B1 (AFB1) is a carcinogenic metabolite produced by certain Aspergillus species. Ochratoxin A (OTA) is classified as “possible carcinogen” and it is a metabolite of Aspergillus ochraceus and Penicillium verrucosum. Fungi contaminate natural and processed olives which support AFB1 and OTA production. The aim of this study was to compare and investigate AFB1 and OTA production in three different varieties of damaged olives. For each variety two different treatments were applied: (1) olives with natural microflora and (2) olives inoculated with A. parasiticus after natural microflora elimination. AFB1 and OTA have been extracted simultaneously from olives, purified with immunoaffinity columns and quantitated by HPLC using fluorescence detector. The recoveries and detection limits of AFB1 and OTA were 94% and 0.15 ng AFB1 g−1 and 102.7%, 0.41 ng OTA g−1 respectively. Results showed that, meanwhile OTA was not found in any olive sample, AFB1 production within the three varieties of olives with natural microflora was significantly ( P ⩽ 0.05 ) different regarding their substrate and time of incubation (18 days). AFB1 production in two different varieties of black olives after inoculation by A. parasiticus was not significantly higher compared with control samples. On the contrary, AFB1 production in green olives was stimulated after the 12th day. Additionally, investigation on the occurrence of AFB1 and OTA in 30 samples of olives and olive pasta from Athens market showed OTA's presence in two samples of olives contaminated at the levels of 1.18 and 1.86 ng OTA g−1. Aflatoxin B1 was found at levels 0.15–1.13 ng AFB1 g−1 in all samples tested.

Aflatoxin B1 (AFB1) is a highly toxic and carcinogenic metabolite produced by certain Aspergillus species on agricultural commodities. Molds isolated from black olives are potentially toxigenic and present a potential health hazard. Olive oil originating from contaminated olives with AFB1 might also be contaminated. The aim of this study was to investigate A. parasiticus growth and AFB1 production in black damaged olives inoculated with 100 conidia flask−1 (1) treated with NaOCl 1.25%, (2) autoclaved at 110°C for 2 min, in comparison to the mold growth and AFB1 production into the yeast extract sucrose (YES) medium under the same conditions of incubation and inoculation. AFB1 extracted from cultures or olives and purified with immunoaffinity columns, was derivatized to its hemiacetal AFB2a and then quantitated by HPLC using fluorescence detector. The recoveries and detection limits from YES and olives were 99.2%, 0.02 ng AFB1 ml−1 and 94%, 0.15 ng AFB1 g−1, respectively. Results showed that mycelia growth was not observed in olives during the 15 days of observation. The maximum growth of A. parasiticus on YES medium was shown on the sixth day. The AFB1 production for both treated with NaOCl and autoclaved olives inoculated or not with A. parasiticus was not significantly different. On the other hand, AFB1 levels produced in olives treated with NaOCl were significantly higher as compared with the autoclaved. The range of contamination of all olive samples inoculated or not for the whole period of observation was 0.15–2.3 ng AFB1 g−1. The production of AFB1 in YES medium on the third, the ninth and the 15th day was ∼1000-, ∼2500- and 10 000-fold higher, respectively, compared with the production in olives thus showing that black damaged olives of Greek origin are not a substrate favorable for AFB1 biosynthesis at hazardous levels. Nevertheless, the production is possible at detectable amounts even after a little contamination that could happen randomly.

Extracts and infusions of wild artichoke ( Cynara cardunculus L.) and globe artichoke ( C. scolymus L.) (heads, bracts and stems) were examined for their total phenolic content (TPC) and their antioxidant activity after performing Classical Extraction (CE) and Ultrasound-Assisted Extraction (UAE). UAE proved to be more effective, since extracts exhibited higher antioxidant activity and TPC values than CE extracts and infusions. Moreover C. cardunculus heads extract using UAE, displayed the maximum TPC values (1.57 mg gallic acid equivalents (GAE) g−1 fresh weight (fw)), the highest DPPH• scavenging activity (IC50; 0.91mg mL−1) and the highest ABTS•+ radical scavenging capacity (2.08 mg Trolox Equivalents (TE) g−1 fw). Moreover, the effect of different concentrations of C. cardunculus head extracts (showing the highest TPC and antioxidant activity) on Aspergillus parasiticus growth was estimated in AFPA medium. The maximum inhibition was found to be ~42.1% in comparison with the control.

Aflatoxin B1 (AFB1) is a highly toxic and carcinogenic metabolite produced by certain Aspergillus species on agricultural commodities. One factor promoting the production of aflatoxin is the presence of high levels of fatty acid hydroperoxides often found in plant material under stress. Jasmonic acid (JA) and its methyl ester (MeJA) are derived from linolenic acid, and their biosyntheses involve the production of lipid hydroperoxides. Exposure of aflatoxigenic mold to jasmonates is likely because the mold attacks plant material and possibly initiates the production of jasmonates. In this study the effect of MeJA on the growth of Aspergillus parasiticus and AFB1 biosynthesis is reported. MeJA, at a final concentration of 10(-4) M in yeast extract sucrose medium, did not have any apparent effect on mycelial growth during the 16 days of observation but did increase significantly the levels of AFB1 after the seventh day of growth. After the ninth day, AFB1 production was decreased in contrast to the control cultures, where the production was constantly increasing. AFB1 determination was performed by immunoaffinity and HPLC after derivatization to AFB2a.

A method is described for the determination of ochratoxin A (OTA) in red wine and vinegar using an acidic chloroform extraction, an immmunoaffinity clean-up step, and a high-performance liquid chromatographic determination with fluorescence detection. The detection limit was estimated at 0.002 microg/liter. The mean recovery factors were found at 91.3 and 96.6% for wine and vinegar, respectively. Thirty-one samples of red wine originating from Mediterranean sea countries and 15 samples of vinegar were examined for the presence of OTA. All red wine samples contained OTA. Seventy-two percent of these samples were found to be contaminated over 0.1 microg/liter. Among them, nine samples contained ochratoxin A in the range of 0.5 to 3.4 microg/liter, 12 samples in the range of 0.10 to 0.50 microg/liter (median: 0.176 microg/liter), and 9 samples in the range of 0.010 to 0.100 microg/liter (median: 0.041 microg/liter). All 15 vinegar samples showed the presence of OTA. The most contaminated ones were three balsamic vinegar samples containing 0.156 microg/liter, 0.102 microg/liter, and 0.252 microg/liter of OTA. In the remaining 12 samples, ochratoxin A levels ranged from 0.008 microg/liter to 0.046 microg/liter (median: 0.012 microg/liter). These data are in good agreement with the hypothesis that wine originating from Southern countries might contain significant OTA concentration and showed the possible occurrence of traces of OTA in vinegar.

Publisher Summary Aflatoxin B1 (AFB1) is produced by the molds Aspergillus flavus and Aspergillus parasiticus, which are able to contaminate food commodities. Since the biosynthesis of AFB1 in food is a very complicated phenomenon, the removal of the mycotoxins would also be difficult, once food has been contaminated. Hence, it is necessary to ensure that olives are stored and handled in a manner that will prevent the growth of aflatoxigenic mold and the production of AFB1. The conditions during the storage of olives can be controlled to a greater extent than in the field, which means in general that it is easier to prevent fungal growth during storage. On the other hand, excessive intake of AFB1 via olive oil could occur in the case of some Greek consumers and other people of the Mediterranean basin as well (depending on their diet). Therefore, it is necessary to apply rigorous regulation for AFB1 as well as for other mycotoxins in virgin olive oil, ensuring in this way a negligible daily intake of AFB1.

Aflatoxin B1 (AFB1) is a carcinogenic metabolite produced by certain Aspergillus species on agricultural commodities. AFB1 biosynthesis is affected by jasmonic acid and also by its methylester (MeJA), a plant growth regulator derived from linoleic acid. This study reports the effect of MeJA on the growth of A. parasiticus and AFB1 output in yeast extract sucrose (YES) medium when added at three different concentrations; namely, 10−2 M, 10−4 M, and 10−6 M. AFB1 determination was performed by immunoaffinity and HPLC. MeJA at 10−4 and 10−6 M concentrations had no significant effect on mycelial growth but did affect AFB1 production after the 7th day of incubation; on the 12th day, AFB1 production was increased by 212.7% and 141.6% compared to the control samples (addition of 10−6 M and 10−4 M MeJA, resp.). Treatment of A. parasiticus cultures with 10−2 M MeJA inhibited mycelial growth and AFB1 production as well. These results suggest that the effect of MeJA on AFB1 biosynthesis by A. parasiticus depends on the MeJA concentration used.

A simple analytical method for ochratoxin A (OTA) determination in grapes is described, using aqueous methanolic extraction, an immunoaffinity column clean-up step and high-performance liquid chromatography with fluorescence detection. Mean recovery was 94% (RSD = 4.0%) with a detection limit of 0.4 ng g(-1) and quantification limit of 1.20 ng g(-1). Repeatability (r) and reproducibility (R) were 1.17 and 1.34, respectively. OTA determinations were applied to 50 grape samples (23 different varieties) originating from representative regions of Greece. Results showed the presence of OTA in 86% of samples tested (n = 50). Traces were found in 56% of samples but OTA was not detectable in 14% of samples. Traces were also found in 4% of red, organically grown samples. The most contaminated were three samples of red grapes, two from Central Greece (2.69 and 1.41 ng g(-1)), both table and wine-making grapes. The third sample (1.46 ng g(-1)), originating from the island of Samos, was used only in wine-making. Mean (1.06 ng g(-1)) and median (0.76 ng g(-1)) OTA concentrations in red grapes were slightly higher compared to the mean (0.82 ng g(-1)) and median (0.65 ng g(-1)) concentrations in white grape samples. The study shows that the potential risk for a person of 60 kg ranged from 0.9 to 9 ng kg(-1) bw day(-1) and is dependent on the quantity of grapes consumed daily.

An improved specific analytical method for ochratoxin A (OTA) determination in olive oil is described, using a methanolic-aqueous extraction, an immunoaffinity column clean up step and high-pressure liquid chromatography with fluorescence detection. The mean recovery was found at 108% (relative standard deviation, RSD = 4.7%) and the detection limit (DL) was estimated at 4.6 ng kg(-1). Along with OTA, aflatoxin B(1) (AFB(1)) was determined using the same extract. The recovery factor was 84.8% (RSD = 17.8%) and the DL was 56 ng kg(-1) olive oil. Both determinations were applied in 50 samples of olive oil originated from representative regions of Greece. Results revealed the presence of OTA in 88% of samples tested (n = 44, mean 267 ng kg(-1)). Among them, 10 were contaminated with more than 500 ng kg(-1) (median 568 ng kg(-1)), 10 with 200-500 ng kg(-1) (median 260 ng kg(-1)), 15 with 100-200 ng kg(-1) (median 140 ng kg(-1)), nine with DL-100 (median 60 ng kg(-1)) and in six samples, OTA was not detectable. Interestingly, most contaminated samples were from Southern Greece. Results of AFB(1) determination showed the presence of aflatoxin B(1) (60 ng kg(-1)) in only one olive oil sample also from Southern Greece. The levels of OTA found in Greek olive oil were relatively low as compared with other commodities such as cereals or wine reported in the literature.