Publications by authors named "Manfred Metzler"

This statement provides scientific guidance on the information needed to support the risk assessment of the detoxification processes applied to products intended for animal feed in line with the acceptability criteria of the Commission Regulation (EU) 2015/786.

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Following a request from the European Commission, the EFSA Panel on Contaminants in the Food Chain (CONTAM) assessed a decontamination process of fish oils and vegetable oils and fats to reduce the concentrations of dioxins (polychlorinated dibenzo--dioxins and polychlorinated dibenzofurans, abbreviated together as PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) by adsorption to activated carbon. All feed decontamination processes must comply with the acceptability criteria specified in the Commission Regulation (EU) 2015/786. Data provided by the feed food business operator (FBO) were assessed for the efficacy of the process and to demonstrate that the process did not adversely affect the characteristics and properties of the product.

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The European Commission has asked the EFSA to evaluate the risk for animal health related to the presence of hydroxymethylfurfural (HMF) in honey bee feed. HMF is a degradation product of particular sugars and can be present in bee feed. HMF is of low acute toxicity in bees but causes increased mortality upon chronic exposure.

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Article Synopsis
  • The EFSA Panel on Contaminants in the Food Chain evaluated a request by the European Commission regarding a detoxification process for groundnut press cake, specifically targeting aflatoxins through ammoniation.
  • The Panel found that while literature suggests the process might lower aflatoxin levels below legal limits, the provided experimental data did not confirm compliance with the necessary safety criteria.
  • They recommended extensive testing to demonstrate reliability and non-reversibility of detoxification, including genotoxicity assessments and analysis of nutritional changes in the feed.
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Fungi of the genus Alternaria infest many agricultural crops and produce numerous mycotoxins, of which altertoxin II (ATX II) is one of the most mutagenic metabolites. ATX II carries an epoxide group but the formation of DNA adducts has not been demonstrated to date. We report now that ATX II gives rise to two covalent adducts with guanine when incubated with DNA under cell-free conditions.

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The European Commission asked EFSA to update their 2006 opinion on ochratoxin A (OTA) in food. OTA is produced by fungi of the genus and and found as a contaminant in various foods. OTA causes kidney toxicity in different animal species and kidney tumours in rodents.

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This paper describes a methodology for hazard assessment of groups of related substances for which toxicity data are insufficient, and which utilises, next to conventional toxicological assessments and mechanistic information, the derivation of relative toxicity potency factors (RPFs). Zearalenone (ZEN) and T-2 toxin (T2) and HT-2 toxin (HT2) and their modified forms have been used as examples. A tolerable daily intake (TDI) for ZEN of 0.

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In 2016, the EFSA Panel on Contaminants in the Food Chain (CONTAM) published a scientific opinion on the acute health risks related to the presence of cyanogenic glycosides (CNGs) in raw apricot kernels in which an acute reference dose (ARfD) of 20 μg/kg body weight (bw) was established for cyanide (CN). In the present opinion, the CONTAM Panel concluded that this ARfD is applicable for acute effects of CN regardless the dietary source. To account for differences in cyanide bioavailability after ingestion of certain food items, specific factors were used.

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The EFSA Panel on Contaminants in the Food Chain (CONTAM) established a tolerable daily intake (TDI) for fumonisin B (FB ) of 1.0 μg/kg body weight (bw) per day based on increased incidence of megalocytic hepatocytes found in a chronic study with mice. The CONTAM Panel considered the limited data available on toxicity and mode of action and structural similarities of FB and found it appropriate to include FB , FB and FB in a group TDI with FB .

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Following a request from the European Commission, the EFSA Panel on Contaminants in the Food Chain (CONTAM) provided a scientific opinion on the assessment of a decontamination process of fish meal. It consisted of extraction of the fish oil, filtration and adsorption with activated carbon, and replacement with decontaminated fish oil in order to reduce the amount of dioxins (polychlorinated dibenzo--dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs)), and dioxin-like (DL-) and non-dioxin-like (NDL-) polychlorinated biphenyls (PCBs). All feed decontamination processes must comply with the acceptability criteria specified in the Commission Regulation (EU) 2015/786.

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Following a request from the European Commission, the EFSA Panel on Contaminants in the Food Chain (CONTAM) provided a scientific opinion on the assessment of a decontamination process for fish meal. This process entails solvent (hexane) extraction of fish oil from fish meal to remove dioxins (polychlorinated dibenzo--dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs)) as well as dioxin-like (DL-) and non-dioxin-like (NDL-) polychlorinated biphenyls (PCBs) followed by replacement with decontaminated fish oil. All feed decontamination processes must comply with the acceptability criteria specified in the Commission Regulation (EU) 2015/786.

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Following a request from the European Commission, the EFSA Panel on Contaminants in the Food Chain (CONTAM) provided a scientific opinion on the assessment of decontamination processes involving the adsorption with activated carbon and physical filtration of fish oil in order to reduce the amount of dioxins (polychlorinated dibenzo--dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs)) and dioxin-like polychlorinated biphenyls (DL-PCBs). All feed decontamination processes must comply with the acceptability criteria specified in the Commission Regulation (EU) 2015/786. Two feed business operators provided data on their respective decontamination processes, which were assessed in terms of the efficacy of the process and the absence of adverse effects in the nature and characteristics of the product after decontamination.

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Following a request from the European Commission, the EFSA Panel on Contaminants in the Food Chain (CONTAM) provided a scientific opinion on the assessment of a decontamination process for the enzymatic treatment and subsequent heating of linseed, in order to reduce the amount of hydrocyanic acid (HCN) present as cyanogenic glycosides. Specifically, it is required that the feed decontamination process is compliant with the acceptability criteria specified in the Commission Regulation (EU) 2015/786 of 19 May 2015. With this aim, the CONTAM Panel assessed the data provided by the feed business operator with respect to the efficacy of the process to remove the contaminant from the linseed batches and on information demonstrating that the process does not adversely affect the characteristics and the nature of the product.

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Following a request from the European Commission, the EFSA Panel on Contaminants in the Food Chain (CONTAM) provided a scientific opinion on the assessment of a decontamination process consisting in the adsorption with activated carbon and physical filtration of fish oil in order to reduce the amount of dioxins (polychlorinated dibenzo--dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs)) and dioxin-like polychlorinated biphenyls (DL-PCBs). All feed decontamination processes must comply with the acceptability criteria specified in the Commission Regulation (EU) 2015/786. The data provided by the feed business operator were assessed with respect to the efficacy of the process and on information demonstrating that the process does not adversely affect the characteristics and the nature of the product.

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The EFSA Panel on Contaminants in the Food Chain (CONTAM) reviewed new studies on nivalenol since the previous opinion on nivalenol published in 2013, but as no new relevant data were identified the tolerable daily intake (TDI) for nivalenol (NIV) of 1.2 μg/kg body weight (bw) established on bases of immuno- and haematotoxicity in rats was retained. An acute reference dose (ARfD) of 14 μg/kg bw was established based on acute emetic events in mink.

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The EFSA Panel on Contaminants in the Food Chain (CONTAM) established a tolerable daily intake (TDI) for T2 and HT2 of 0.02 μg/kg body weight (bw) per day based on a new subchronic toxicity study in rats that confirmed that immune- and haematotoxicity are the critical effects of T2 and using a reduction in total leucocyte count as the critical endpoint. An acute reference dose (ARfD) of 0.

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The mycotoxins alternariol and alternariol-9-O-methyl ether have recently been reported to be extensively conjugated with glucose and malonyl glucose in tobacco suspension cells. However, only trace amounts of glucosylated conjugates were detected in tomatoes inoculated with Alternaria alternata in the present study. Instead, mostly sulfate conjugates were observed.

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The Alternaria mycotoxins alternariol (AOH) and altertoxin II (ATX II) have previously been shown to elicit mutagenic and genotoxic effects in bacterial and mammalian cells, although with vastly different activities. For example, ATX II was about 50 times more mutagenic than AOH. We now report that stemphyltoxin III (STTX III) is also highly mutagenic.

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The mycotoxins alternariol (AOH) and alternariol-9-O-methyl ether (AME) carry three and two phenolic hydroxyl groups, respectively, which makes them candidates for the formation of conjugated metabolites in plants. Such conjugates may escape routine methods of analysis and have therefore been termed masked or, more recently, modified mycotoxins. We report now that AOH and AME are extensively conjugated in suspension cultures of tobacco BY-2 cells.

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The mycotoxin sterigmatocystin (STC) has an aflatoxin-like structure including a furofuran ring system. Like aflatoxin B1, STC is a liver carcinogen and forms DNA adducts after metabolic activation to an epoxide at the furofuran ring. In incubations of STC with human P450 isoforms, one monooxygenated and one dioxygenated STC metabolite were recently reported, and a GSH adduct was formed when GSH was added to the incubations.

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Altertoxins I-III, alterlosins I and II, alteichin (alterperylenol), stemphyltoxins I-IV, stemphyperylenol, stemphytriol, 7-epi-8-hydroxyaltertoxin I, and 6-epi-stemphytriol are mycotoxins derived from perylene quinone, for which the absolute configuration was not known. Electronic circular dichroism (ECD) spectra were calculated for these compounds and compared with measured spectra of altertoxins I-III, alteichin, and stemphyltoxin III and with reported Cotton effects. Specific rotations were calculated and compared with reported specific rotations.

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Alternaria alternata is a filamentous fungus that causes considerable loss of crops of economically important feed and food worldwide. It produces more than 60 different secondary metabolites, among which alternariol (AOH) and altertoxin (ATX) are the most important mycotoxins. We found that mycotoxin production and spore formation are regulated by light in opposite ways.

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The group of perylene quinone-type Alternaria toxins contains several congeners with epoxide groups, for example, altertoxin II (ATX II) and stemphyltoxin III (STTX III). Recent studies in our laboratory have disclosed that the epoxide moieties of ATX II and STTX III are reduced to alcohols in human colon Caco-2 cells, thereby resulting in the formation of altertoxin I (ATX I) and alteichin, respectively. In the present study, this pathway was demonstrated for ATX II in three other mammalian cell lines.

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The absorption of four Alternaria toxins with perylene quinone structures, i.e. altertoxin (ATX) I and II, alteichin (ALTCH) and stemphyltoxin (STTX) III, has been determined in the Caco-2 cell Transwell system, which represents a widely accepted in vitro model for human intestinal absorption and metabolism.

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