Combined hazard assessment of mycotoxins and their modified forms applying relative potency factors: Zearalenone and T2/HT2 toxin.

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 0.25 µg/kg bw was established. In vitro and in vivo studies suggested that modified forms of ZEN act via the same mode of action as ZEN (oestrogenicity). Results from in vivo uterotrophic assays were used to establish RPFs, allowing inclusion the different modified forms in a group TDI with ZEN. A TDI for the sum of T2/HT2 of 0.02 µg/kg bw per day and an acute reference dose (ARfD) of 0.3 µg/kg bw for the sum of T2/HT2 was established. In vitro studies show that phase I metabolites of T2/HT2 act via a similar mode of action as their parent compounds, namely protein synthesis inhibition with immune- and haematotoxicity. The phase I metabolites as well as conjugates of T2/HT2 and their phase I metabolites can be included in a group TDI with T2/HT2 applying RPFs.

Re-evaluation of oxidised soya bean oil interacted with mono- and diglycerides of fatty acids (E 479b) as a food additive.

The EFSA Panel on Food Additives and Flavourings (FAF) provides a scientific opinion re-evaluating the safety of thermally oxidised soya bean oil interacted with mono- and diglycerides of fatty acids (TOSOM) (E 479b) when used as a food additive. The Scientific Committee on Food (SCF) and the Joint FAO/WHO Expert Committee on Food Additives (JECFA) derived an acceptable daily intake (ADI) of 25 and 30 mg/kg body weight (bw) per day, respectively. There was no reliable information regarding the absorption, distribution, metabolism, excretion (ADME) for TOSOM. No adverse effects have been detected in a limited subchronic toxicity study in pigs. The Panel identified a no observed adverse effect level (NOAEL) of 5,400, the highest dose tested, from a chronic and carcinogenicity study in rats. No genotoxicity data were available. No reliable studies for reproductive or developmental toxicity were available. From the chronic and carcinogenicity study, no lesions in reproductive organs were described and the lack of carcinogenic effect alleviated the concern for genotoxicity at the first site of contact. The Panel concluded that the available toxicological data were insufficient to support the current ADI, in particular, due to the lack of ADME data and absence of developmental toxicity studies TOSOM (E 479b) is only authorised in one food category and only one reported use level that equals the maximum permitted level was submitted. The estimated high (P95) exposure reached an upper value of 10.1 mg/kg bw per day for toddlers. When comparing the highest estimated exposure of 10 mg/kg bw per day in toddlers with the NOAEL of 5,400 mg/kg bw per day (the highest dose tested), the margin of safety (MoS) would be 540. Therefore, the Panel considered the use of TOSOM (E 479b) to be of no safety concern, in particular when considering the limited current use of this food additive. The Panel also recommended some modifications of the EU specifications for E 479b.

Risks to human and animal health related to the presence of moniliformin in food and feed.

Moniliformin (MON) is a mycotoxin with low molecular weight primarily produced by Fusarium fungi and occurring predominantly in cereal grains. Following a request of the European Commission, the CONTAM Panel assessed the risk of MON to human and animal health related to its presence in food and feed. The limited information available on toxicity and on toxicokinetics in experimental and farm animals indicated haematotoxicity and cardiotoxicity as major adverse health effects of MON. MON causes chromosome aberrations in vitro but no in vivo genotoxicity data and no carcinogenicity data were identified. Due to the limitations in the available toxicity data, human acute or chronic health-based guidance values (HBGV) could not be established. The margin of exposure (MOE) between the no-observed-adverse-effect level (NOAEL) of 6.0 mg/kg body weight (bw) for cardiotoxicity from a subacute study in rats and the acute upper bound (UB) dietary exposure estimates ranged between 4,000 and 73,000. The MOE between the lowest benchmark dose lower confidence limit (for a 5% response - BMDL05) of 0.20 mg MON/kg bw per day for haematological hazards from a 28-day study in pigs and the chronic dietary human exposure estimates ranged between 370 and 5,000,000 for chronic dietary exposures. These MOEs indicate a low risk for human health but were associated with high uncertainty. The toxicity data available for poultry, pigs, and mink indicated a low or even negligible risk for these animals from exposure to MON in feed at the estimated exposure levels under current feeding practices. Assuming similar or lower sensitivity as for pigs, the CONTAM Panel considered a low or even negligible risk for the other animal species for which no toxicity data suitable for hazard characterisation were identified. Additional toxicity studies are needed and depending on their outcome, the collection of more occurrence data on MON in food and feed is recommended to enable a comprehensive human risk assessment.

Re-evaluation of sodium, potassium and calcium salts of fatty acids (E 470a) and magnesium salts of fatty acids (E 470b) as food additives.

The EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS) provides a scientific opinion re-evaluating the safety of sodium, potassium and calcium salts of fatty acids (E 470a) and magnesium salts of fatty acids (E 470b) when used as food additives. In 1991, the Scientific Committee on Food (SCF) established a group acceptable daily intake (ADI) 'not specified' for the fatty acids (myristic-, stearic-, palmitic- and oleic acid) and their salts. The sodium, potassium, calcium and magnesium salts of fatty acids are expected to dissociate in the gastrointestinal tract to fatty acid carboxylates and their corresponding cations. There were no data on subchronic toxicity, chronic toxicity, reproductive and developmental toxicity of the salts of fatty acids. There was no concern for mutagenicity of calcium caprylate, potassium oleate and magnesium stearate. From a carcinogenicity study with sodium oleate, a no observed adverse effect level (NOAEL) could not be identified but the substance was considered not to present a carcinogenic potential. Palmitic- and stearic acid which are the main fatty acids in E 470a and E 470b were already considered of no safety concern in the re-evaluation of the food additive E 570. The fatty acid moieties of E 470a and E 470b contributed maximally for 5% to the overall intake of saturated fatty acids from all dietary sources. Overall, the Panel concluded that there was no need for a numerical ADI and that the food additives sodium, potassium, calcium and magnesium salts of fatty acids (E 470a and E 470b) were of no safety concern at the reported uses and use levels.

Risk to human and animal health related to the presence of 4,15-diacetoxyscirpenol in food and feed.

4,15-Diacetoxyscirpenol (DAS) is a mycotoxin primarily produced by Fusarium fungi and occurring predominantly in cereal grains. As requested by the European Commission, the EFSA Panel on Contaminants in the Food Chain (CONTAM) assessed the risk of DAS to human and animal health related to its presence in food and feed. Very limited information was available on toxicity and on toxicokinetics in experimental and farm animals. Due to the limitations in the available data set, human acute and chronic health-based guidance values (HBGV) were established based on data obtained in clinical trials of DAS as an anticancer agent (anguidine) after intravenous administration to cancer patients. The CONTAM Panel considered these data as informative for the hazard characterisation of DAS after oral exposure. The main adverse effects after acute and repeated exposure were emesis, with a no-observed-adverse-effect level (NOAEL) of 32 µg DAS/kg body weight (bw), and haematotoxicity, with a NOAEL of 65 µg DAS/kg bw, respectively. An acute reference dose (ARfD) of 3.2 µg DAS/kg bw and a tolerable daily intake (TDI) of 0.65 µg DAS/kg bw were established. Based on over 15,000 occurrence data, the highest acute and chronic dietary exposures were estimated to be 0.8 and 0.49 µg DAS/kg bw per day, respectively, and were not of health concern for humans. The limited information for poultry, pigs and dogs indicated a low risk for these animals at the estimated DAS exposure levels under current feeding practices, with the possible exception of fattening chicken. Assuming similar or lower sensitivity than for poultry, the risk was considered overall low for other farm and companion animal species for which no toxicity data were available. In consideration of the similarities of several trichothecenes and the likelihood of co-exposure via food and feed, it could be appropriate to perform a cumulative risk assessment for this group of substances.

Re-evaluation of calcium silicate (E 552), magnesium silicate (E 553a(i)), magnesium trisilicate (E 553a(ii)) and talc (E 553b) as food additives.

The EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS) provides a scientific opinion re-evaluating the safety of calcium silicate (E 552), magnesium silicate (E 553a) and talc (E 553b) when used as food additives. In 1991, the Scientific Committee on Food (SCF) established a group acceptable daily intake (ADI) 'not specified' for silicon dioxide and silicates. The EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS) recently provided a scientific opinion re-evaluating the safety of silicon dioxide (E 551) when used as a food additive. The Panel noted that the absorption of silicates and talc was very low; there was no indication for genotoxicity or developmental toxicity for calcium and magnesium silicate and talc; and no confirmed cases of kidney effects have been found in the EudraVigilance database despite the wide and long-term use of high doses of magnesium trisilicate up to 4 g/person per day over decades. However, the Panel considered that accumulation of silicon from calcium silicate in the kidney and liver was reported in rats, and reliable data on subchronic and chronic toxicity, carcinogenicity and reproductive toxicity of silicates and talc were lacking. Therefore, the Panel concluded that the safety of calcium silicate (E 552), magnesium silicate (E 553a(i)), magnesium trisilicate (E 553a(ii)) and talc (E 553b) when used as food additives cannot be assessed. The Panel considered that there is no mechanistic rationale for a group ADI for silicates and silicon dioxide and the group ADI established by the SCF is obsolete. Based on the food supplement scenario considered as the most representative for risk characterisation, exposure to silicates (E 552-553) for all population groups was below the maximum daily dose of magnesium trisilicate used as an antacid (4 g/person per day). The Panel noted that there were a number of approaches, which could decrease the uncertainties in the current toxicological database. These approaches include - but are not limited to - toxicological studies as recommended for a Tier 1 approach as described in the EFSA Guidance for the submission of food additives and conducted with an adequately characterised material. Some recommendations for the revision of the EU specifications were proposed by the Panel.

Re-evaluation of locust bean gum (E 410) as a food additive.

Following a request from European Commission, the EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS) provides a scientific opinion re-evaluating the safety of locust bean gum (E 410) as a food additive. Locust bean gum (E 410) is an authorised food additive in the EU. Locust bean gum (E 410) as specified in the Commission Regulation (EU) No 231/2012 is derived from the ground endosperm of the seeds of the strains of carob tree, Ceratonia siliqua (L.) Taub. (Family Leguminosae). An acceptable daily intake (ADI) 'not specified' was allocated by the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives (JECFA) in 1981. Although not evaluated by the Scientific Committee for Food (SCF), it was accepted by the SCF in 1991 for use in weaning food, and in 1994, in infant formulae for special medical purposes. Locust bean gum is practically undigested, not absorbed intact, but significantly fermented by enteric bacteria in humans. No adverse effects were reported in 90-day toxicity and carcinogenicity studies in rodents at the highest doses tested and there was no concern with respect to the genotoxicity and to reproductive and developmental toxicity of locust bean gum (E 410). The Panel concluded that there is no need for a numerical ADI for locust bean gum (E 410), and that there is no safety concern for the general population at the refined exposure assessment for its reported uses as a food additive. However, infants and young children consuming foods for special medical purposes may show a higher susceptibility to gastrointestinal effects of locust bean gum due to their underlying medical condition. The Panel concluded that the available data do not allow an adequate assessment of the safety of locust bean gum (E 410) in these foods for infants and young children.

Re-evaluation of oxidised starch (E 1404), monostarch phosphate (E 1410), distarch phosphate (E 1412), phosphated distarch phosphate (E 1413), acetylated distarch phosphate (E 1414), acetylated starch (E 1420), acetylated distarch adipate (E 1422), hydroxypropyl starch (E 1440), hydroxypropyl distarch phosphate (E 1442), starch sodium octenyl succinate (E 1450), acetylated oxidised starch (E 1451) and starch aluminium octenyl succinate (E 1452) as food additives.

Following a request from the European Commission, the EFSA Panel on Food Additives and Nutrient sources added to Food (ANS) was asked to deliver a scientific opinion on the re-evaluation of 12 modified starches (E 1404, E 1410, E 1412, E 1413, E 1414, E 1420, E 1422, E 1440, E 1442, E 1450, E 1451 and E 1452) authorised as food additives in the EU in accordance with Regulation (EC) No 1333/2008 and previously evaluated by JECFA and the SCF. Both committees allocated an acceptable daily intake (ADI) 'not specified'. In humans, modified starches are not absorbed intact but significantly hydrolysed by intestinal enzymes and then fermented by the intestinal microbiota. Using the read-across approach, the Panel considered that adequate data on short- and long-term toxicity and carcinogenicity, and reproductive toxicity are available. Based on in silico analyses, modified starches are considered not to be of genotoxic concern. No treatment-related effects relevant for human risk assessment were observed in rats fed very high levels of modified starches (up to 31,000 mg/kg body weight (bw) per day). Modified starches (e.g. E 1450) were well tolerated in humans up to a single dose of 25,000 mg/person. Following the conceptual framework for the risk assessment of certain food additives, the Panel concluded that there is no safety concern for the use of modified starches as food additives at the reported uses and use levels for the general population and that there is no need for a numerical ADI. The combined exposure to E 1404-E 1451 at the 95th percentile of the refined (brand-loyal) exposure assessment scenario for the general population was up to 3,053 mg/kg bw per day. Exposure to E 1452 for food supplement consumers only at the 95th percentile was up to 22.1 mg/kg bw per day.

Re-evaluation of guar gum (E 412) as a food additive.

The Panel on Food Additives and Nutrient Sources added to Food (ANS) provides a scientific opinion re-evaluating the safety of guar gum (E 412) as a food additive. In the EU, guar gum was evaluated by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) in 1970, 1974 and 1975, who allocated an acceptable daily intake (ADI) 'not specified'. Guar gum has been also evaluated by the Scientific Committee for Food (SCF) in 1977 who endorsed the ADI 'not specified' allocated by JECFA. Following the conceptual framework for the risk assessment of certain food additives re-evaluated under Commission Regulation (EU) No 257/2010, the Panel considered that adequate exposure and toxicity data were available. Guar gum is practically undigested, not absorbed intact, but significantly fermented by enteric bacteria in humans. No adverse effects were reported in subchronic and carcinogenicity studies at the highest dose tested; no concern with respect to the genotoxicity. Oral intake of guar gum was well tolerated in adults. The Panel concluded that there is no need for a numerical ADI for guar gum (E 412), and there is no safety concern for the general population at the refined exposure assessment of guar gum (E 412) as a food additive. The Panel considered that for uses of guar gum in foods intended for infants and young children the occurrence of abdominal discomfort should be monitored and if this effect is observed doses should be identified as a basis for further risk assessment. The Panel considered that no adequate specific studies addressing the safety of use of guar gum (E 412) in food categories 13.1.5.1 and 13.1.5.2 were available. Therefore, the Panel concluded that the available data do not allow an adequate assessment of the safety of guar gum (E 412) in infants and young children consuming these foods for special medical purposes.

Re-evaluation of glycerol (E 422) as a food additive.

The ANS Panel provides a scientific opinion re-evaluating the safety of glycerol (E 422) used as a food additive. In 1981, the Scientific Committee on Food (SCF) endorsed the conclusion from the Joint FAO/WHO Expert Committee on Food Additives (JECFA) in 1976 of 'acceptable daily intake (ADI) for man not specified'. The Panel concluded that glycerol has low acute toxicity and that local irritating effects of glycerol in the gastrointestinal tract reported in some gavage studies was likely due to hygroscopic and osmotic effects of glycerol. Glycerol did not raise concern with respect to genotoxicity and was of no concern with regard to carcinogenicity. Reproductive and prenatal developmental studies were limited to conclude on reproductive toxicity but no dose-related adverse effects were reported. None of the animal studies available identified an adverse effect for glycerol. The Panel conservatively estimated the lowest oral dose of glycerol required for therapeutic effect to be 125 mg/kg bw per hour and noted that infants and toddlers can be exposed to that dose by drinking less than the volume of one can (330 mL) of a flavoured drink. The Panel concluded that there is no need for a numerical ADI and no safety concern regarding the use of glycerol (E 422) as a food additive at the refined exposure assessment for the reported uses. The Panel also concluded that the manufacturing process of glycerol should not allow the production of a food additive, which contains genotoxic and carcinogenic residuals at a level which would result in a margin of exposure below 10,000. The Panel recommended modification of the EU specifications for E 422. The Panel also recommended that more information on uses and use levels and analytical data should be made available to the Panel.

Re-evaluation of polyglycerol polyricinoleate (E 476) as a food additive.

The Panel on Food Additives and Nutrient Sources added to Food (ANS) provides a scientific opinion re-evaluating the safety of polyglycerol polyricinoleate (PGPR, E 476) used as a food additive. In 1978, the Scientific Committee for Food (SCF) established an acceptable daily intake (ADI) of 7.5 mg/kg body weight (bw) per day for PGPR. PGPR is hydrolysed in the gut resulting in the liberation of free polyglycerols, polyricinoleic acid and ricinoleic acid. Di- and triglycerol are absorbed and excreted unchanged in the urine; long-chain polyglycerols show lower absorption and are mainly excreted unchanged in faeces. Acute oral toxicity of PGPR is low, and short-term and subchronic studies indicate PGPR is tolerated at high doses without adverse effects. PGPR (E 476) is not of concern with regard to genotoxicity or carcinogenicity. The single reproductive toxicity study with PGPR was limited and was not an appropriate study for deriving a health-based guidance value. Human studies with PGPR demonstrated that there is no indication of significant adverse effect. The Panel considered a 2-year combined chronic toxicity/carcinogenicity study for determining a reference point and derived a no observed adverse effect level (NOAEL) for PGPR (E 476) of 2,500 mg/kg bw per day, the only dose tested. Therefore, the Panel concluded that the present data set give reason to revise the ADI of 7.5 mg/kg bw per day allocated by SCF to 25 mg/kg bw per day. Exposure estimates did not exceed the ADI of 25 mg/kg bw per day and a proposed extension of use would not result in an exposure exceeding this ADI. The Panel recommended modification of the EU specifications for PGPR (E 476).

Re-evaluation of acacia gum (E 414) as a food additive.

The Panel on Food Additives and Nutrient Sources added to Food (ANS) provides a scientific opinion re-evaluating the safety of acacia gum (E 414) as a food additive. In the EU, acacia gum has not been formally evaluated by the Scientific Committee for Food (SCF), and therefore, no ADI has been allocated. However, it was accepted for use in weaning food (SCF, 1991). In 1999, the SCF considered 'that the use of acacia gum/gum arabic in coatings for nutrient preparations containing trace elements is acceptable provided carry-over levels in infant formulae, follow-on formulae or FSMP do not exceed 10 mg/kg'. Acacia gum was evaluated by JECFA in 1982 and 1990 and the specifications were amended in 1998. Based on the lack of adverse effects in the available toxicity studies, an ADI 'not specified' was allocated. Following the conceptual framework for the risk assessment of certain food additives re-evaluated under Commission Regulation (EU) No 257/2010, the Panel considered that adequate exposure and toxicity data were available. Acacia gum is unlikely to be absorbed intact and is slightly fermented by intestinal microbiota. No adverse effects were reported in subchronic and carcinogenicity studies at the highest dose tested and there is no concern with respect to the genotoxicity. Oral daily intake of a large amount of acacia gum up to 30,000 mg acacia gum/person per day (approximately equivalent 430 mg acacia gum/kg bw per day) for up to 18 days was well tolerated in adults but some individuals experienced flatulence which was considered by the Panel as undesirable but not adverse effect. The Panel concluded that there is no need for a numerical ADI for acacia gum (E 414), and there is no safety concern for the general population at the refined exposure assessment of acacia gum (E 414) as a food additive.

Statement on the validity of the conclusions of a mouse carcinogenicity study on sucralose (E 955) performed by the Ramazzini Institute.

The Panel on Food Additives and Nutrient Sources added to Food (ANS) was requested from the European Commission to provide a statement on the validity of the conclusions of a mouse study on the carcinogenic potential of sucralose (E 955) performed by the Ramazzini Institute (Soffritti et al., 2016). Sucralose (E 955) is authorised as a food additive in the EU in accordance with Annex II to Regulation (EC) No 1333/2008 on food additives. According to Commission Regulation (EU) No 257/2010, the full re-evaluation of sucralose shall be completed by December 2020. Taking into consideration the publication from Soffritti et al. (2016), the technical report and additional information provided by the Ramazzini Institute and other information available for sucralose (E 955), the Panel noted: (i) the design of the bioassay that considers exposure from gestation up to natural death of animals implies an increase in background pathology that results in the possibility of misclassifications and a difficult interpretation of data, especially in the absence of both an appropriate concurrent control group and a recent historical database; (ii) the lack of a dose-response relationship between the exposure to sucralose and incidence of lymphomas and leukaemias (combined); (iii) the lack of a mode of action and failure to meet all the Bradford-Hill considerations for a cause-effect relationship between intake of sucralose and the development of tumours in male mice only; (iv) a comprehensive database was available for sucralose and no carcinogenic effect was reported in adequate studies in rats and mice. Moreover, there was no reliable evidence of in vivo genotoxicity. Therefore, the Panel concluded that the available data did not support the conclusions of the authors (Soffritti et al., 2016) that sucralose induced haematopoietic neoplasias in male Swiss mice.

Re-evaluation of tragacanth (E 413) as a food additive.

The Panel on Food Additives and Nutrient Sources added to Food (ANS) provides a scientific opinion re-evaluating the safety of tragacanth (E 413) as a food additive. In the EU, tragacanth (E 413) has been evaluated by the Scientific Committee for Food (SCF, 1989) and by the Joint FAO/WHO Expert Committee on Food Additives (JECFA, 1987), who both allocated an acceptable daily intake (ADI) 'not specified' for this gum. Following the conceptual framework for the risk assessment of certain food additives, re-evaluated under Commission Regulation (EU) No 257/2010, the Panel considered that adequate exposure and toxicity data were available. Tragacanth (E 413) is unlikely to be absorbed intact and is partially fermented by intestinal microbiota. No adverse effects were reported in carcinogenicity studies at the highest dose tested and there is no concern with respect to the genotoxicity. Oral daily intake of a large amount of tragacanth up to 9,900 mg tragacanth/person per day (approximately equivalent 141 mg tragacanth/kg body weight (bw) per day) for up to 21 days was well tolerated in humans. The Panel concluded that there is no need for a numerical ADI for tragacanth (E 413) and that there is no safety concern for the general population at the refined exposure assessment of tragacanth (E 413) as a food additive at the reported uses and use levels.

Re-evaluation of potassium nitrite (E 249) and sodium nitrite (E 250) as food additives.

The Panel on Food Additives and Nutrient Sources added to Food (ANS) provided a scientific opinion re-evaluating the safety of potassium nitrite (E 249) and sodium nitrite (E 250) when used as food additives. The ADIs established by the SCF (1997) and by JECFA (2002) for nitrite were 0-0.06 and 0-0.07 mg/kg bw per day, respectively. The available information did not indicate in vivo genotoxic potential for sodium and potassium nitrite. Overall, an ADI for nitrite per se could be derived from the available repeated dose toxicity studies in animals, also considering the negative carcinogenicity results. The Panel concluded that an increased methaemoglobin level, observed in human and animals, was a relevant effect for the derivation of the ADI. The Panel, using a BMD approach, derived an ADI of 0.07 mg nitrite ion/kg bw per day. The exposure to nitrite resulting from its use as food additive did not exceed this ADI for the general population, except for a slight exceedance in children at the highest percentile. The Panel assessed the endogenous formation of nitrosamines from nitrites based on the theoretical calculation of the NDMA produced upon ingestion of nitrites at the ADI and estimated a MoE > 10,000. The Panel estimated the MoE to exogenous nitrosamines in meat products to be < 10,000 in all age groups at high level exposure. Based on the results of a systematic review, it was not possible to clearly discern nitrosamines produced from the nitrite added at the authorised levels, from those found in the food matrix without addition of external nitrite. In epidemiological studies there was some evidence to link (i) dietary nitrite and gastric cancers and (ii) the combination of nitrite plus nitrate from processed meat and colorectal cancers. There was evidence to link preformed NDMA and colorectal cancers.

Re-evaluation of sodium nitrate (E 251) and potassium nitrate (E 252) as food additives.

The Panel on Food Additives and Nutrient Sources added to Food (ANS) provided a scientific opinion re-evaluating the safety of sodium nitrate (E 251) and potassium nitrate (E 252) when used as food additives. The current acceptable daily intakes (ADIs) for nitrate of 3.7 mg/kg body weight (bw) per day were established by the SCF (1997) and JECFA (2002). The available data did not indicate genotoxic potential for sodium and potassium nitrate. The carcinogenicity studies in mice and rats were negative. The Panel considered the derivation of an ADI for nitrate based on the formation of methaemoglobin, following the conversion of nitrate, excreted in the saliva, to nitrite. However, there were large variations in the data on the nitrate-to-nitrite conversion in the saliva in humans. Therefore, the Panel considered that it was not possible to derive a single value of the ADI from the available data. The Panel noticed that even using the highest nitrate-to-nitrite conversion factor the methaemoglobin levels produced due to nitrite obtained from this conversion would not be clinically significant and would result to a theoretically estimated endogenous N-nitroso compounds (ENOC) production at levels which would be of low concern. Hence, and despite the uncertainty associated with the ADI established by the SCF, the Panel concluded that currently there was insufficient evidence to withdraw this ADI. The exposure to nitrate solely from its use as a food additive was estimated to be less than 5% of the overall exposure to nitrate in food based on a refined estimated exposure scenario. This exposure did not exceed the current ADI (SCF, 1997). However, if all sources of exposure to dietary nitrate are considered (food additive, natural presence and contamination), the ADI would be exceeded for all age groups at the mean and the highest exposure.

Re-evaluation of tara gum (E 417) as a food additive.

The Panel on Food Additives and Nutrient Sources added to Food (ANS) provides a scientific opinion re-evaluating the safety of tara gum (E 417) as a food additive. Tara gum (E 417) has been evaluated by the EU Scientific Committee for Food (SCF, 1992) and by the Joint FAO/WHO Expert Committee on Food Additives (JECFA, 1987), who both allocated an acceptable daily intake (ADI) 'not specified' for this gum. Following the conceptual framework for the risk assessment of certain food additives, re-evaluated under Commission Regulation (EU) No 257/2010, the Panel considered that adequate exposure and toxicity data were available for tara gum (E 417). Tara gum (E 417) is unlikely to be absorbed intact and is expected to be fermented by intestinal microbiota. No adverse effects were reported at the highest doses tested in subchronic, chronic and carcinogenicity studies and there is no concern with respect to the genotoxicity. The Panel concluded that there is no need for a numerical ADI for tara gum (E 417) and that there is no safety concern for the general population at the refined exposure assessment of tara gum (E 417) as a food additive at the reported uses and use levels.

Re-evaluation of xanthan gum (E 415) as a food additive.

The Panel on Food Additives and Nutrient Sources added to Food (ANS) provides a scientific opinion re-evaluating the safety of xanthan gum (E 415) as food additive. Following the conceptual framework for the risk assessment of certain food additives re-evaluated under Commission Regulation (EU) No 257/2010, the Panel considered that adequate exposure and toxicity data were available. Based on the reported use levels, a refined exposure of up to 64 mg/kg bw per day in children for the general population, 38 mg/kg bw per day for children consumers only of food supplements at the high level exposure and 115 mg/kg bw per day for infants consuming foods for special medical purposes and special formulae (FSMPs), were estimated. Xanthan gum (E 415) is unlikely to be absorbed intact and is expected to be fermented by intestinal microbiota. No adverse effects were reported at the highest doses tested in chronic and carcinogenicity studies and there is no concern with respect to the genotoxicity. Repeated oral intake by adults of xanthan gum up to 214 mg/kg bw per day for ten days was well tolerated, but some individuals experienced abdominal discomfort, an undesirable but not adverse effect. The Panel concluded that there is no need for a numerical ADI for xanthan gum (E 415), and that there is no safety concern for the general population at the refined exposure assessment of xanthan gum (E 415) as food additive. Considering the outcome of clinical studies and post-marketing surveillance, the Panel concluded that there is no safety concern from the use of xanthan gum (E 415) in FSMPs for infants and young children at concentrations reported by the food industry. The current re-evaluation of xanthan gum (E 415) as a food additive is not considered to be applicable for infants under the age of 12 weeks.

Prevalidation of the rat CFU-GM assay for in vitro toxicology applications.

In vitro haematotoxicity assays are thought to have the potential to significantly reduce and refine the use of animals for haematotoxicity testing. These assays are used successfully in all types of studies - however, their use is not so common in human toxicology studies in the preclinical setting, as they are not required for regulatory testing in this case. Furthermore, these assays could play a key role in bridging the gap between preclinical toxicology studies in animal models and clinical investigations. In previous studies, the Colony Forming Unit-Granulocyte Macrophage (CFU-GM) assay has been validated for testing drug haematotoxicity (with both mouse bone-marrow and human cord blood) and for predicting the in vivo human maximal tolerated dose (MTD) by adjusting in vivo data on mouse toxicity. Recently, a Colony Forming Unit-Megakaryocyte (CFU-MK) assay has also been prevalidated for testing drug toxicity toward megakaryocytes. The rat CFU-GM assay has been used by many researchers for its ability to evaluate in vitro haematotoxicity. Although it is not yet available, a standardised procedure for data comparison could be very important, since the rat is the most widely-used species for the in vivo testing of toxicants. This report presents the results of the prevalidation study developed to analyse the intra-laboratory and inter-laboratory variability of a standardised operating procedure for this assay and its performance for the in vitro determination of the inhibitory concentration (IC) values of drugs on rat myeloid progenitors (CFU-GM). The results demonstrate that the CFU-GM assay can be performed with cryopreserved rat bone-marrow cells (rBMC). The assay represents a useful tool for evaluating the toxicity of a compound, in terms of both relative toxicity (when different molecules are compared) and the prediction of the degree of in vivo toxicity. The use of this assay could greatly reduce the number of rats used in experimental procedures, and could also contribute to the accumulation of more toxicity data on compounds to be registered according to the criteria established by the European Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) programme.

Synthesis and antitumor activity of novel dibutyltin carboxylates of aminoglucosyl derivatives.

In this study, di-n-butyltin(IV) oxide was reacted with the amino glucose analog, cis-4-[N-(1',3',4',6'-tetra-O-benzoyl-2-deoxy-glucopyranosyl)imido]-4-oxo-2-butenoic acid (1a) and o-[N-(1',3',4',6'-tetra-O-benzoyl-2-deoxy-glucopyranosyl) carbamoyl] benzoic acid (2a) to give the complexes bis-{cis-4-[N-(1',3',4',6'-tetra-O-benzoyl-2-deoxy-glucopyranosyl)imido-4-oxo-2-butenoic acid]-di-n-butyltin} carboxylate (1) and bis-{o-[N-(1',3',4',6'-tetra-O-benzoyl-2-deoxy-glucopyranosyl) carbamoyl-benzoic acid]-di-n-butyltin}carboxylate (2). These two compounds were then characterized by IR, NMR and MS. In vitro tests showed that both compounds have high cytotoxicity in four tumor cell lines (P388, HL-60, A549 and BEL-7402). Clonogenic assays demonstrated that both compounds 1 and 2 have hematopoietic cell toxicity at 10(-6) M.