Following a request from the European Commission, in accordance with Regulation (EC) No 1331/2008 establishing a common authorisation procedure for food additives, food enzymes and food flavourings, the Panel on Food Additives and Nutrient Sources added to Food (ANS) was asked to deliver a scientific opinion on the safety of the proposed use of potassium polyaspartate (A-5D K/SD) as a stabiliser in wine. According to the applicant potassium polyaspartate (A-5D K/SD) is proposed for use as a stabiliser against tartrate crystal precipitation (anti-scaling additive) in wine (red, rosé and white wine) at a maximum level (ML) of use of 300 mg/L.
According to the applicant, potassium polyaspartate (A-5D K/SD) is proposed for use as a stabiliser against tartrate crystal precipitation in wine (red, rosé and white wine) at the typical use level of 100‑200 mg/L and an ML of 300 mg/L, depending on the level of instability of the wine to be treated. The food category for which an authorisation is sought with the current application is 14.2 Alcoholic beverages, including alcohol-free and low-alcohol counterparts.
The Panel based its opinion on a dossier submitted by the applicant and on the additional clarification provided upon request from the European Food Safety Authority (EFSA) during the assessment process. The tiered approach to toxicological testing described in the 2012 ANS Panel ‘Guidance for submission for food additive evaluations’ was followed by the applicant and the minimal biological and toxicological dataset applicable to all compounds was submitted for evaluation by the Panel. Following the evaluation of the Tier 1 toxicological studies described below, the Panel did not request additional testing to be conducted.
The EFSA Comprehensive European Food Consumption Database was used to estimate the dietary exposure. Dietary exposure to potassium polyaspartate (A-5D K/SD) from its use as a food additive was estimated combining the food consumption data available within the EFSA Comprehensive European Food Consumption Database with the proposed MLs and the proposed typical use levels provided by the applicant. Different exposure scenarios were calculated. Uncertainties on the exposure assessment were identified and discussed with regard to their impact on the final exposure calculation.
Potassium polyaspartate (A-5D K/SD) is the potassium salt of polyaspartic acid, produced from l-aspartic acid and potassium hydroxide. The applicant has proposed specifications of 98% purity for the material. The Panel considered that the analytical information provided on five batches of the proposed food additive, produced independently according to the method of manufacture, showed that the additive can be consistently manufactured within its proposed specifications.
According to the applicant, the presence of potassium polyaspartate (A-5D K/SD) in red or white wine can be determined and quantified by calculating the difference in aspartic acid content before and after complete sample hydrolysis to aspartic acid monomer.
The applicant has provided information on the stability of the food additive potassium polyaspartate (A-5D K/SD) at different storage conditions, as well as in water and in wine.
The applicant submitted results from two in vitro tests aimed at assessing gastrointestinal digestibility and intestinal absorption of potassium polyaspartate (A-5D K/SD): a sequential proteolytic attack with pepsin (porcine) and pancreatin (porcine), and an absorption study in human colon adenocarcinoma Caco-2 cells in vitro. The results from these studies showed that proteolytic digestion of potassium polyaspartate (A-5D K/SD) was minimal and that no absorption of intact A-5D K/SD was observed in vitro.
The genotoxic potential of potassium polyaspartate (A-5D K/SD) was investigated in a bacterial reverse mutation assay and using an in vitro mammalian cell micronucleus test. No genotoxic effect was observed in either of these two standard regulatory studies carried out in recognised testing facilities according to the relevant guideline and Good Laboratory Practice (GLP) compliance and reported in accordance with the relevant guideline.
Data from two toxicity studies performed in rats were submitted as part of the dossier, a 14-day range-finding study performed to collect information of target organs and to appropriate dosing, and a 90-day subchronic toxicity study. The 90-day study was performed in accordance with the OECD Test Guideline 408, modified to include assessment of additional parameters to allow for the identification of chemicals with the potential to cause neurotoxic, immunological or reproductive organ effects or endocrine-mediated effects. In this study, potassium polyaspartate (A-5D K/SD) was administered daily via gavage to groups of Wistar rats (10 animals per sex per dose), at doses of 250, 500 and 1,000 mg/kg bw per day.
Based on the findings of this study, the Panel considered that a no observed adverse effect level (NOAEL) of potassium polyaspartate (A-5D K/SD) was to be set at 1,000 mg/kg bw per day, the highest dose tested, and also that there were no triggers for additional toxicological testing.
The mean dietary exposure from the proposed use level of 200 mg/L ranged from 0.01 to 0.2 mg/kg bw per day in adults up to 0.04 to 0.4 mg/kg bw per day in the elderly. The high-level intake ranged from 0 to 1.0 in adults and from 0.3 to 1.2 mg/kg bw per day in the elderly.
At the proposed maximum level of 300 mg/L, the mean dietary exposure ranged from 0.02 to 0.4 mg/kg bw per day in adults up to 0.05 to 0.6 mg/kg bw per day in the elderly. The high-level intake ranged from 0 to 1.4 in adults and from 0.4 to 1.8 mg/kg bw per day in the elderly.
In consideration of the proposed use of potassium polyaspartate (A-5D K/SD) as a food additive, limited to wine, the Panel considered it appropriate to consider dietary exposure only in adults and in the elderly. The Panel acknowledged that data from the younger age groups (i.e. infants, toddlers, children and adolescents) showed some levels of intake from wine or other alcoholic consumption. Consumption of alcoholic beverages is not appropriate for these age groups, and these exposure estimates, which are very low, are most likely a result of the indirect consumption of alcoholic beverages (ranging from < 0.001 up to 0.10 mg/kg bw per day) as recipe ingredients of composite foods. Therefore, the Panel considered that these were not relevant for the current risk assessment.
Based on the NOAEL of the 90-day study and these exposure estimates, the Panel considered that there would be an adequate margin of safety from the proposed use and use levels (approximately 550 for the high-level elderly consumers at the proposed ML of 300 mg/L).
The Panel considered that the estimated margin of safety of 550 was higher than the value of 200 which could be derived for the uncertainty factor based on the default safety factors for toxicokinetics and toxicodynamics and extrapolation from a 90-day study to chronic exposure when using a 90-day study to derive an acceptable daily intake (ADI) (EFSA SC, 2012).
The Panel noted that the NOAEL of 1,000 mg/kg bw per day was the highest dose tested and that the exposure used for this comparison is a conservative estimate because the applicant indicated that for most wines typical levels of 100 to 200 mg/L of potassium polyaspartate (A-5D K/SD) would be sufficient. The Panel considers that, because of the possible uncertainties, the margin of safety estimated above is likely to be lower than the actual margin of safety.
Based on 4% breakdown of aspartic acid, the Panel estimated that the maximal amount of aspartic acid released would be 0.04 mg/kg bw per day at the typical use level and 0.07 mg/kg bw per day at the proposed ML. This intake could be compared with the estimates of dietary intake of aspartic acid estimates of mean and high-level exposure to aspartate ions from the diet (9.1 and 13 g/day, respectively, which is equivalent to approximately 130 and 186 mg/kg bw per day). The Panel considered that this additive use would increase dietary exposures by less than 0.05% at the proposed ML which it considered negligible.
The Panel concluded that there was no safety concern from the proposed use and use levels of potassium polyaspartate (A-5D K/SD) as a stabiliser in wine.
The Panel recommended that specifications for potassium polyaspartate (A-5D K/SD) should be revised in order to define limits for the possible presence of toxic elements and to clarify the identity of the other significant impurities.