Possible Adverse Effects of Food Additive E171 (Titanium Dioxide) Related to Particle Specific Human Toxicity, Including the Immune System.

Titanium dioxide (TiO2) is used as a food additive (E171) and can be found in sauces, icings, and chewing gums, as well as in personal care products such as toothpaste and pharmaceutical tablets. Along with the ubiquitous presence of TiO2 and recent insights into its potentially hazardous properties, there are concerns about its application in commercially available products. Especially the nano-sized particle fraction (<100 nm) of TiO2 warrants a more detailed evaluation of potential adverse health effects after ingestion. A workshop organized by the Dutch Office for Risk Assessment and Research (BuRO) identified uncertainties and knowledge gaps regarding the gastrointestinal absorption of TiO2, its distribution, the potential for accumulation, and induction of adverse health effects such as inflammation, DNA damage, and tumor promotion. This review aims to identify and evaluate recent toxicological studies on food-grade TiO2 and nano-sized TiO2 in ex-vivo, in-vitro, and in-vivo experiments along the gastrointestinal route, and to postulate an Adverse Outcome Pathway (AOP) following ingestion. Additionally, this review summarizes recommendations and outcomes of the expert meeting held by the BuRO in 2018, in order to contribute to the hazard identification and risk assessment process of ingested TiO2.

Pattern of risks of systemic lupus erythematosus among statin users: a population-based cohort study.

OBJECTIVES: To examine the association between the use of statins and the risk of systemic lupus erythematosus (SLE) with focus on describing the patterns of risks over time. SETTING: A population-based cohort study using the UK Clinical Practice Research Datalink. PARTICIPANTS: All patients aged 40 years or older who had at least one prescription of statins during the period 1995-2009 were selected and matched by age, sex, practice and date of first prescription to non-users. The follow-up period of statin users was divided into periods of current, recent and past exposure, with patients moving among these three exposure categories over time. Current statin users were also stratified into ≤1 year or >1 year of use. MAIN OUTCOME MEASURES: Time-dependent Cox models were used to calculate HRs of SLE, adjusted for disease history and previous drug exposure. RESULTS: We included 1 039 694 patients, of whom 519 847 were statin users. Current statin users did not have an increased risk of developing SLE among patients aged ≥40 years (HRadjusted 0.75, 95% CI 0.53 to 1.07). Current statin users who continued the therapy for >1 year had a 38% lower risk of developing SLE (HRadjusted 0.62, 95% CI 0.42 to 0.93). When more specific definitions for SLE were used, this latter finding, however, was not observed. CONCLUSIONS: Our findings showed no effect of statins on the risk of developing SLE among patients aged ≥40 years. Further research is needed to study the long-term effects of statins on SLE.

Titanium dioxide food additive (E171) induces ROS formation and genotoxicity: contribution of micro and nano-sized fractions.

Since 1969, the European Union approves food-grade titanium dioxide (TiO2), also known as E171 colouring food additive. E171 is a mixture of micro-sized particles (MPs) and nano-sized particles (NPs). Previous studies have indicated adverse effects of oral exposure to E171, i.e. facilitation of colon tumour growth. This could potentially be partially mediated by the capacity to induce reactive oxygen species (ROS). The aim of the present study is to determine whether E171 exposure induces ROS formation and DNA damage in an in vitro model using human Caco-2 and HCT116 cells and to investigate the contribution of the separate MPs and NPs TiO2 fractions to these effects. After suspension of the particles in Hanks' balanced salt solution buffer and cell culture medium with either bovine serum albumin (BSA) or foetal bovine serum, characterization of the particles was performed by dynamic light scattering, ROS formation was determined by electron spin/paramagnetic resonance spectroscopy and DNA damage was determined by the comet and micronucleus assays. The results showed that E171, MPs and NPs are stable in cell culture medium with 0.05% BSA. The capacity for ROS generation in a cell-free environment was highest for E171, followed by NPs and MPs. Only MPs were capable to induce ROS formation in exposed Caco-2 cells. E171, MPs and NPs all induced single-strand DNA breaks. Chromosome damage was shown to be induced by E171, as tested with the micronucleus assay in HCT116 cells. In conclusion, E171 has the capability to induce ROS formation in a cell-free environment and E171, MPs and NPs have genotoxic potential. The capacity of E171 to induce ROS formation and DNA damage raises concerns about potential adverse effects associated with E171 (TiO2) in food.

Inhibition of CXCL12-mediated chemotaxis of Jurkat cells by direct immunotoxicants.

Directional migration of cells to specific locations is required in tissue development, wound healing, and immune responses. Immune cell migration plays a crucial role in both innate and adaptive immunity. Chemokines are small pro-inflammatory chemoattractants that control the migration of leukocytes. In addition, they are also involved in other immune processes such as lymphocyte development and immune pathology. In a previous toxicogenomics study using the Jurkat T cell line, we have shown that the model immunotoxicant TBTO inhibited chemotaxis toward the chemokine CXCL12. In the present work, we aimed at assessing a novel approach to detecting chemicals that affect the process of cell migration. For this, we first evaluated the effects of 31 chemicals on mRNA expression of genes that are known to be related to cell migration. With this analysis, seven immunotoxicants were identified as potential chemotaxis modulators, of which five (CoCl2 80 µM, MeHg 1 µM, ochratoxin A 10 µM, S9-treated ochratoxin A 10 µM, and TBTO 100 nM) were confirmed as chemotaxis inhibitor in an in vitro trans-well chemotaxis assay using the chemokine CXCL12. The transcriptome data of the five compounds together with previously obtained protein phosphorylation profiles for two out of five compounds (i.e., ochratoxin A and TBTO) revealed that the mechanisms behind the chemotaxis inhibition are different for these immunotoxicants. Moreover, the mTOR inhibitor rapamycin had no effect on the chemotaxis of Jurkat cells, indicating that the mTOR pathway is not involved in CXCL12-mediated chemotaxis of Jurkat cells, which is opposite to the findings on human primary T cells (Munk et al. in PLoS One 6(9):e24667, 2011). Thus, the results obtained from the chemotaxis assay conducted with Jurkat cells might not fully represent the results obtained with human primary T cells. Despite this difference, the present study indicated that some compounds may exert their immunotoxic effects through inhibition of CXCL12-mediated chemotaxis.

Developmental immunotoxicity of chemicals in rodents and its possible regulatory impact.

Around 25% of the children in developed countries are affected with immune-based diseases. Juvenile onset diseases such as allergic, inflammatory and autoimmune diseases have shown increasing prevalences in the last decades. The role of chemical exposures in these phenomena is unclear. It is thought that the developmental immune system is more susceptible to toxicants than the mature situation. Developmental immunotoxicity (DIT) testing is nowadays not or minimally included in regulatory toxicology requirements. We reviewed whether developmental immune parameters in rodents would provide relatively sensitive endpoints of toxicity, whose inclusion in regulatory toxicity testing might improve hazard identification and risk assessment of chemicals. For each of the nine reviewed toxicants, the developing immune system was found to be at least as sensitive or more sensitive than the general (developmental) toxicity parameters. Functional immune (antigen-challenged) parameters appear more affected than structural (non-challenged) immune parameters. Especially, antibody responses to immune challenges with keyhole limpet hemocyanine or sheep red blood cells and delayed-type hypersensitivity responses appear to provide sensitive parameters of developmental immune toxicity. Comparison with current tolerable daily intakes (TDI) and their underlying overall no observed adverse effect levels showed that for some of the compounds reviewed, the TDI may need reconsideration based on developmental immune parameters. From these data, it can be concluded that the developing immune system is very sensitive to the disruption of toxicants independent of study design. Consideration of including functional DIT parameters in current hazard identification guidelines and wider application of relevant study protocols is warranted.

Developmental immunotoxicity testing of 4-methyl anisole.

The developmental immunotoxicity of 4-methyl anisole (4MA) was investigated in the rat. Four study designs were used, with either premating or post-weaning onset of exposure, continued to postnatal day 50, and with or without additional oral gavage of pups from postnatal day 10 onward. Reduced litter size (benchmark dose lower confidence limit (BMDL) 80mg/kg bw/day) was the most sensitive developmental parameter, with pup relative organ weight effects observed at similar BMDLs, in the absence of maternal toxicity. Eosinophil numbers were reduced at lower doses (BMDL 16mg/kg bw/day). KLH challenge resulted in increased IL-13 and TNF-α responses, and variably reduced IgG production (BMDL 27mg/kg bw/day). T4 levels were reduced by 11% at maximum with a BMDL of 73mg/kg bw/day. Differences between exposure cohorts were limited and were considered to be without biological significance. This study shows that 4MA induces developmental immunotoxicity at doses below those inducing developmental and general toxicity. These observations being independent of the study designs applied suggest that the post-weaning period, included in all designs, is the most relevant sensitive period for inducing 4MA mediated developmental immunotoxicity. Moreover, this study stresses the importance of including developmental immunotoxicity testing by default in regulatory toxicology.

Successful validation of genomic biomarkers for human immunotoxicity in Jurkat T cells in vitro.

Previously, we identified 25 classifier genes that were able to assess immunotoxicity using human Jurkat T cells. The present study aimed to validate these classifiers. For that purpose, Jurkat cells were exposed for 6 h to subcytotoxic doses of nine immunotoxicants, five non-immunotoxicants and four compounds for which human immunotoxicity has not yet been fully established. RNA was isolated and subjected to Fluidigm quantitative real time (qRT)-PCR analysis. The sensitivity, specificity and accuracy of the screening assay as based on the nine immunotoxicants and five non-immunotoxicants used in this study were 100%, 80% and 93%, respectively, which is better than the performance in our previous study. Only one compound was classified as false positive (benzo-e-pyrene). Of the four potential (non-)immunotoxicants, chlorantraniliprole and Hidrasec were classified immunotoxic and Sunset yellow and imidacloprid as non-immunotoxic. ToxPi analysis of the PCR data provided insight in the molecular pathways that were affected by the compounds. The immunotoxicants 2,3-dichloro-propanol and cypermethrin, although structurally different, affected protein metabolism and cholesterol biosynthesis and transport. In addition, four compounds, i.e. chlorpyrifos, aldicarb, benzo-e-pyrene and anti-CD3, affected genes in cholesterol metabolism and transport, protein metabolism and transcription regulation. qRT-PCR on eight additional genes coding for similar processes as defined in ToxPi analyzes, supported these results. In conclusion, the 25 immunotoxic classifiers performed very well in a screening with new non-immunotoxic and immunotoxic compounds. Therefore, the Jurkat screening assay has great promise to be applied within a tiered approach for animal free testing of human immunotoxicity.

Anchoring molecular mechanisms to the adverse outcome pathway for skin sensitization: Analysis of existing data.

Allergic contact dermatitis (ACD) is a hypersensitivity immune response induced by small protein-reactive chemicals. Currently, the murine local lymph node assay (LLNA) provides hazard identification and quantitative estimation of sensitizing potency. Given the complexity of ACD, a single alternative method cannot replace the LLNA, but it is necessary to combine methods through an integrated testing strategy (ITS). In the development of an ITS, information regarding mechanisms and molecular processes involved in skin sensitization is crucial. The recently published adverse outcome pathway (AOP) for skin sensitization captures mechanistic knowledge into key events that lead to ACD. To understand the molecular processes in ACD, a systematic review of murine in vivo studies was performed and an ACD molecular map was constructed. In addition, comparing the molecular map to the limited human in vivo toxicogenomic data available suggests that certain processes are similarly triggered in mice and humans, but additional human data will be needed to confirm these findings and identify differences. To gain insight in the molecular mechanisms represented by various human in vitro systems, the map was compared to in vitro toxicogenomic data. This analysis allows for comparison of emerging in vitro methods on a molecular basis, in addition to mathematical predictive value. Finally, a survey of the current in silico, in chemico, and in vitro methods was used to indicate which AOP key event is modeled by each method. By anchoring emerging classification methods to the AOP and the ACD molecular map, complementing methods can be identified, which provides a cornerstone for the development of a testing strategy that accurately reflects the key events in skin sensitization.

Immunotoxicity of silver nanoparticles in an intravenous 28-day repeated-dose toxicity study in rats.

BACKGROUND: Nanosilver is used in a variety of medical and consumer products because of its antibacterial activity. This wide application results in an increased human exposure. Knowledge on the systemic toxicity of nanosilver is, however, relatively scarce. In a previous study, the systemic toxicity of 20 nm silver nanoparticles (Ag-NP) was studied in a 28-day repeated-dose toxicity study in rats. Ag-NP were intravenously administered with a maximum dose of 6 mg/kg body weight (bw)/day. Several immune parameters were affected: reduced thymus weight, increased spleen weight and spleen cell number, a strongly reduced NK cell activity, and reduced IFN-γ production were observed. METHODS: Prompted by these affected immune parameters, we wished to assess exposure effects on the functional immune system. Therefore, in the present study the T-cell dependent antibody response (TDAR) to keyhole limpet hemocyanin (KLH) was measured in a similar 28-day intravenous repeated-dose toxicity study. In addition, a range of immunological parameters was measured. Data obtained using the benchmark dose (BMD) approach were analyzed by fitting dose-response models to the parameters measured. RESULTS: A reduction in KLH-specific IgG was seen, with a lowest 5% lower confidence bound of the BMD (BMDL) of 0.40 mg/kg bw/day. This suggests that Ag-NP induce suppression of the functional immune system. Other parameters sensitive to Ag-NP exposure were in line with our previous study: a reduced thymus weight with a BMDL of 0.76 mg/kg bw/day, and an increased spleen weight, spleen cell number, and spleen cell subsets, with BMDLs between 0.36 and 1.11 mg/kg bw/day. Because the effects on the spleen are not reflected by increased KLH-specific IgG, they, however, do not suggest immune stimulation. CONCLUSIONS: Intravenous Ag-NP administration in a 28-day repeated-dose toxicity study induces suppression of the functional immune system. This finding underscores the importance to study the TDAR to evaluate immunotoxicity and not to rely solely on measuring immune cell subsets.

Particle size dependent deposition and pulmonary inflammation after short-term inhalation of silver nanoparticles.

BACKGROUND: Although silver nanoparticles are currently used in more than 400 consumer products, it is not clear to what extent they induce adverse effects after inhalation during production and use. In this study, we determined the lung burden, tissue distribution, and the induction and recovery of adverse effects after short-term inhalation exposure to 15 nm and 410 nm silver nanoparticles. METHODS: Rats were nose-only exposed to clean air, 15 nm silver nanoparticles (179 µg/m³) or 410 nm silver particles (167 µg/m³) 6 hours per day, for four consecutive days. Tissue distribution and the induction of pulmonary toxicity were determined at 24 hours and 7 days after exposure and compared with the internal alveolar dose. Presence of silver nanoparticles in lung cells was visualized by transmission electron microscopy (TEM). RESULTS: Exposure to 15 nm silver nanoparticles induced moderate pulmonary toxicity compared to the controls, indicated by a 175-fold increased influx of neutrophils in the lungs, a doubling of cellular damage markers in the lungs, a 5-fold increase in pro-inflammatory cytokines, and a 1.5-fold increase in total glutathione at 24 hours after exposure. All the observed effects disappeared at 7 days after exposure. No effects were observed after exposure to 410 nm silver particles. The internal alveolar mass dose of the 15 nm nanoparticles was 3.5 times higher compared to the 410 nm particles, which equals to a 66,000 times higher particle number. TEM analysis revealed 15 nm nanoparticles in vesicles and nuclei of lung cells, which were decreased in size to <5 nm at 24 hours after exposure. This demonstrates substantial dissolution of the silver nanoparticles. CONCLUSION: The results show a clear size-dependent effect after inhalation of similar mass concentrations of 15 nm and 410 nm silver (nano)particles. This can be partially explained by the difference in the internal alveolar dose between the 15 nm and 410 nm silver (nano)particles as well as by a difference in the release rate of silver ions.

Transcriptome-based functional classifiers for direct immunotoxicity.

Current screening methods for direct immunotoxic chemicals are mainly based on general toxicity studies with rodents. The present study aimed to identify transcriptome-based functional classifiers that can eventually be exploited for the development of in vitro screening assays for direct immunotoxicity. To this end, a toxicogenomics approach was applied in which gene expression changes in human Jurkat lymphoblastic T cells were investigated in response to a wide range of compounds, including direct immunotoxicants, immunosuppressive drugs, and non-immunotoxic control chemicals. On the basis of DNA microarray data previously obtained by the exposure of Jurkat cells to 31 test compounds (Shao et al. in Toxicol Sci 135(2):328-346, 2013), we identified a set of 93 genes, of which 80 were significantly regulated (|numerical ratio| ≥1.62) by at least three compounds and the other 13 genes were significantly regulated by either one single compound or compound class. A total of 28 most differentially regulated genes were selected for qRT-PCR verification using a training set of 44 compounds consisting of the above-mentioned 31 compounds (23 immunotoxic and 8 non-immunotoxic) and 13 additional immunotoxicants. Good correlation between the results of microarray and qRT-PCR (Pearson's correlation, R ≥ 0.69) was found for 27 out of the 28 genes. Redundancy analysis of these 27 potential classifiers led to a final set of 25 genes. To assess the performance of these genes, Jurkat cells were exposed to 20 additional compounds (external verification set) followed by qRT-PCR. The classifier set of 25 genes gave a good performance in the external verification: accuracy 85 %, true positive rate (sensitivity) 88 %, and true negative rate (specificity) 67 %. Furthermore, on the basis of the gene ontology annotation of the 25 classifier genes, the immunotoxicants examined in this study could be categorized into distinct functional subclasses. In conclusion, we have identified and validated classifier genes that can be used for the development of an in vitro assay for the identification and initial characterization of hazards for direct immunotoxicity of chemicals and drugs. This assay promises to complement animal-free toxicity testing approaches within the field of direct immunotoxicity.

Assessment of the risk of respiratory sensitization from fragrance allergens released by air fresheners.

Consumers using air fresheners are exposed to the emitted ingredients, including fragrances, via the respiratory tract. Several fragrances are known skin sensitizers, but it is unknown whether inhalation exposure to these chemicals can induce respiratory sensitization. Effects on the immune system were assessed by testing a selection of five fragrance allergens in the respiratory local lymph node assay (LLNA). The probability and extent of exposure were assessed by measuring concentrations of the 24 known fragrance allergens in 109 air fresheners. It was shown that the most frequently used fragrances in air fresheners were D-limonene and linalool. In the respiratory LLNA, these fragrances were negative. Of the other tested chemicals, only isoeugenol induced a statistically significant increase in cell proliferation. Consumer exposure was assessed in more detail for D-limonene, linalool, and isoeugenol by using exposure modeling tools. It was shown that the most frequently used fragrances in air fresheners, D-limonene, and linalool gave rise to a higher consumer exposure compared with isoeugenol. To evaluate whether the consumer exposure to these fragrances is low or high, these levels were compared with measured air concentrations of diisocyanates, known human respiratory sensitizers. This comparison showed that consumer exposure from air fresheners to D-limonene, linalool, and isoeugenol is considerably lower than occupational exposure to diisocyanates. By combing this knowledge on sensitizing potency with the much lower exposure compared to diisocyanates it seems highly unlikely that isoeugenol can induce respiratory sensitization in consumers using air fresheners.

Evaluating the performance of integrated approaches for hazard identification of skin sensitizing chemicals.

The currently available animal-free methods for the detection of skin sensitizing potential of chemicals seem promising. However, no single method is able to comprehensively represent the complexity of the processes involved in skin sensitization. To ensure a mechanistic basis and cover the complexity, multiple methods should be integrated into a testing strategy, in accordance with the adverse outcome pathway that describes all key events in skin sensitization. Although current majority voting testing strategies have proven effective, the performance of individual methods is not taken into account. To that end, we designed a tiered strategy based on complementary characteristics of the included methods, and compared it to a majority voting approach. This tiered testing strategy was able to correctly identify all 41 chemicals tested. In terms of total number of experiments required, the tiered testing strategy requires less experiments compared to the majority voting approach. On the other hand, this tiered strategy is more complex due the number of different alternative methods required, and predicted costs are similar for both strategies. Both the tiered and majority voting strategies provide a mechanistic basis for skin sensitization testing, but the strategy most suitable for regulatory decision-making remains to be determined.

The immunosuppressant tributyltin oxide blocks the mTOR pathway, like rapamycin, albeit by a different mechanism.

We treated the thymoma cell line (EL4) with two model immunosuppressants, rapamycin and tributyltin oxide (TBTO), and compared their effects on the expression levels of proteins that are downstream targets of mTOR kinase 1 (mammalian target of rapamycin, known also as mechanistic target of rapamycin): p70 ribosomal S6 kinase1 and 4E-binding protein 1, a repressor of the cap-binding protein eIF4E. In addition, we evaluated the levels of ribosomal protein S6, p-eIF4B, substrates of p70S6 kinase1, matrin 3 and ribonucleotide reductase, subunit RRM2. The levels of these proteins were evaluated in cell lysates by immunoblot. We found that both compounds inhibited the phosphorylation state of p70S6 kinase 1 and its substrates; however, TBTO, in contrast to rapamycin, reduced the level of the total p70S6k1. Besides, we detected a band with a molecular weight of c. 32 kDa only in the TBTO-treated lysates. This band was detected with a monoclonal antibody specific for S6k1, suggesting that this band might be a degradation product of the kinase. Further, TBTO and rapamycin differentially affected 4E-binding protein 1; the former compound stimulated its phosphorylation state whereas the latter inhibited it. The two immunosuppressants did not affect the level of ribonucleotide reductase, but TBTO downregulated matrin3, in agreement with a previous report, whereas rapamycin had no effect on the expression level of this latter protein. We conclude that TBTO inhibits, like rapamycin, the p70 S6 kinase 1 pathway, but with a different mechanism. However, in contrast to rapamycin, which inhibits the cap-dependent translation, TBTO increases the phosphorylation of 4E-binding protein1.

Safety evaluation of an extension of use of the food enzyme thermolysin from the non-genetically modified Anoxybacillus caldiproteolyticus strain AE-TP.

The food enzyme thermolysin (EC. 3.4.24.27) is produced with the non-genetically modified Anoxybacillus caldiproteolyticus strain AE-TP by Amano Enzyme Inc. A safety evaluation of this food enzyme was made previously, in which EFSA concluded that this food enzyme did not give rise to safety concerns when used in eight food manufacturing processes. Subsequently, the applicant has requested to extend its use to one additional process, to withdraw two processes and to revise the use levels. In this assessment, EFSA updated the safety evaluation of this food enzyme for use in a total of seven food manufacturing processes. The dietary exposure to the food enzyme-total organic solids (TOS) was calculated to be up to 0.989 mg TOS/kg body weight (bw) per day in European populations. When combined with the no observed adverse effect level reported in the previous opinion (700 mg TOS/kg bw per day, the mid-dose tested), the Panel derived a revised margin of exposure of at least 708. Based on the data provided for the previous evaluation and the revised margin of exposure in the present evaluation, the Panel concluded that this food enzyme does not give rise to safety concerns under the revised intended conditions of use.

Safety evaluation of an extension of use of the food enzyme oryzin from the non-genetically modified Aspergillus ochraceus strain AE-P.

The food enzyme oryzin (EC 3.4.21.63) is produced with the non-genetically modified Aspergillus ochraceus strain AE-P by Amano Enzyme Inc. A safety evaluation of this food enzyme was made previously, in which EFSA concluded that this food enzyme did not give rise to safety concerns when used in nine food manufacturing processes. Subsequently, the applicant has requested to extend its use to one additional process, to withdraw two food processes and to revise the use levels. In this assessment, EFSA updated the safety evaluation of this food enzyme when used in a total of eight food manufacturing processes. The dietary exposure to the food enzyme-total organic solids (TOS) was calculated to be up to 0.354 mg TOS/kg body weight (bw) per day in European populations. When combined with the no observed adverse effect level reported in the previous opinion (1862 mg TOS/kg bw per day, the highest dose tested), the Panel derived a margin of exposure of at least 5260. Based on the data provided for the previous evaluation and the revised margin of exposure in the present evaluation, the Panel concluded that this food enzyme does not give rise to safety concerns under the revised intended conditions of use.

Safety evaluation of the food enzyme lysophospholipase from the genetically modified Trichoderma reesei strain DP-Nyc81.

The food enzyme lysophospholipase (2-lysophosphatidylcholine acylhydrolase, EC 3.1.1.5) is produced with the genetically modified Trichoderma reesei strain DP-Nyc81 by Genencor International B.V. The genetic modifications do not give rise to safety concerns. The food enzyme is free from viable cells of the production organism and its DNA. It is intended to be used in the processing of cereals and other grains for the production of glucose syrups and other starch hydrolysates. Since residual amounts of food enzyme-total organic solids are removed during these food manufacturing processes, dietary exposure was not calculated and toxicological studies were considered unnecessary. A search for the identity of the amino acid sequence of the food enzyme to known allergens was made and no match was found. The Panel considered that the risk of allergic reactions upon dietary exposure cannot be excluded, but the likelihood is low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns, under the intended conditions of use.

Safety evaluation of the food enzyme rennet containing chymosin and pepsin A from the abomasum of suckling calves, goats, lambs and buffaloes.

The food enzyme containing chymosin (EC 3.4.23.4) and pepsin (EC 3.4.23.1) is prepared from the abomasum of suckling calves, goats, lambs and buffaloes by Caglificio Clerici S.p.A. It is intended to be used in the production of cheese. As no concerns arise from the source of the food enzyme, from its manufacture and based on the history of safe use and consumption, the Panel considered that toxicological data were not required and no exposure assessment was necessary. The similarity of the amino acid sequences of the two proteins (chymosin and pepsin A) to those of known allergens was searched and two matches were found with respiratory allergens. The Panel considered that the risk of allergic reactions by dietary exposure cannot be excluded, but the likelihood is low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Safety evaluation of the food enzyme asparaginase from the genetically modified Aspergillus niger strain AGN.

The food enzyme asparaginase (l-asparagine amidohydrolase; EC 3.5.1.1) is produced with the genetically modified Aspergillus niger strain AGN by DSM Food Specialties B.V. The genetic modifications do not give rise to safety concerns. The food enzyme is free from viable cells of the production organism and its DNA. It is intended to be used to prevent acrylamide formation in food processing. The dietary exposure to the food enzyme-total organic solids (TOS) was estimated to be up to 1.434 mg TOS/kg body weight (bw) per day in European populations. The toxicity studies were carried out with an asparaginase from A. niger (strain ASP). The Panel considered this food enzyme as a suitable substitute for the asparaginase to be used in the toxicological studies, because the genetic differences between the production strains are not expected to result in a different toxigenic potential, and the raw materials and manufacturing processes of both food enzymes are comparable. Genotoxicity tests did not indicate a safety concern. The systemic toxicity was assessed by means of a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 1038 mg TOS/kg bw per day, which, when compared with the estimated dietary exposure, resulted in a margin of exposure of at least 724. A search for the similarity of the amino acid sequence of the food enzyme to known allergens was made and no match was found. The Panel considered that the risk of allergic reactions by dietary exposure cannot be excluded, but the likelihood is low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.