Re‐evaluation of gellan gum (E 418) as food additive

The present opinion deals with the re‐evaluation of the safety of gellan gum (E 418) used as a food additive.

Gellan gum (E 418) is authorised as a food additive in the European Union (EU) in accordance with Annex II and Annex III to Regulation (EC) No 1333/2008 on food additives and specific purity criteria have been defined in the Commission Regulation (EU) No 231/20121.

In the EU, gellan gum (E 418) has been evaluated by the Scientific Committee for Food (SCF) in 1990 (SCF, 1992). The committee allocated an acceptable daily intake (ADI) ‘not specified’ based on the toxicological data and the use levels, typically ranging from 0.1% to 1%, as a gelling, stabilising or thickening agent. Specific dietary or medical uses were not covered by the SCF evaluation. Furthermore in the SCF evaluation was pointed out that the specifications should exclude the presence of viable Pseudomonas elodea. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) evaluated gellan gum in 1991 (JECFA, 1991b) and revised the specifications twice thereafter (JECFA, 20062014). JECFA ‘Committee allocated an ADI ‘not specified’ to gellan gum, and pointed out that its potential laxative effect at high intakes should be taken into account when it is used as a food additive’.

According to Commission Regulation (EU) No 231/2012, gellan gum (E 418) is a high molecular weight polysaccharide gum produced by a pure culture fermentation of a carbohydrate by strains of P. elodea. The Panel noted that according to available information gellan gum (E 418) is produced by only one bacterial strain ATCC 31461.

The repeating unit of the polysaccharide is a tetrasaccharide composed of two d‐glucose units, one d‐glucuronic acid residue and one of l‐rhamnose residue and is substituted with acyl groups (glycerate and acetate groups as O‐glycosidically linked esters).

According to the industry, in addition to the gellan gum polysaccharide, typical samples contain water (2–14%), proteinaceous material measured by nitrogen content (%N = 0–3.0%) (Documentation provided to EFSA No 3) and may contain polyhydroxybutyrate (PHB) up to 25 wt% (Baird and Cleary, 1994).

There are two basic forms: ‘high acyl’ and ‘low acyl’ form of the food additive gellan gum (E 418), which are distinguished by the degree of substitution by O‐acyl groups. For ‘low acyl’ (including fully deacylated) type, there are both clarified and non‐clarified products available on the market.

The Panel noted that, according to the available information from the industry, the content of PHB in dried gellan gum was estimated to be from less than 1% up to 25%, depending on the degree of deacylation and clarification. The Panel noted that PHB may be a major component of the food additive E 418 resulting from the manufacturing process. In the absence of any justification about its technological need, the Panel considered that its presence should be limited, and/or at least indicated in the specifications of the food additive E 418. In this regard, the Panel noted that clarification is a feasible mean to reduce the amount of PHB in E 418.

In the period from the date of US Patent of Kang and Veeder (1982) to which the production of gellan gum originally refers until the present time, no reports have been identified that the strain ATCC 31461 was the cause of any human infection.

The biological and toxicological testing has been performed with a deacylated gellan gum or with a gellan gum of unknown degree of acylation. However, the Panel considered that the structural similarities of the different types of gellan gum allowed for read across. No information was available on the purity of the test material in these studies, including the concentration of PHB.

The in vivo metabolic and physiological studies of gellan gum indicated that this compound would not be absorbed intact. In rats, there is indication of limited increased production of short‐chain fatty acid (SCFA) and the faecal release of acetate and butyrate could be the consequence of both the hydrolysis of the acetyl side chain of gellan gum and the possible presence of PHB. In humans, gellan gum would not be absorbed intact and there is no indication of significant fermentation by the intestinal microbiota.

Gellan gum is of low acute toxicity.

Subchronic toxicity studies with gellan gum conducted in rats and dogs did not reveal adverse effects at the highest doses tested (equal to 2,950 mg/kg body weight (bw) per day for males and 3,760 mg/kg bw per day for females in rats and 1,870 mg/kg bw day for males and 2,070 mg/kg bw per day for females in dogs). In a short‐term study in rhesus monkeys, no adverse effects were seen at 3,000 mg gellan gum/kg bw per day, the highest dose tested.

Based on the available data, the Panel considered that gellan gum did not raise concern with respect to genotoxicity.

Gellan gum is not of concern with respect to carcinogenicity. Chronic toxicity studies with gellan gum did not reveal adverse effects at the highest doses tested equal to 2,867 mg gellan gum/kg bw per day for male mice and 3,627 mg gellan gum/kg bw per day for female mice, or equivalent to 1,460 mg gellan gum/kg bw per day in rats.

A dietary two‐generation reproductive toxicity study, an one‐generation study (in uterophase of a chronic/carcinogenicity study) and a prenatal developmental toxicity study in rats with gellan gum up to 5% in the diet (1,460 mg/kg bw per day), the highest dose tested, did not show adverse effects.

The consumption of up to 200 mg/kg bw per day gellan gum over 3 weeks had no adverse health effects in humans. There was no indication for allergenic reaction to gellan gum both in animals and humans.

To assess the dietary exposure to gellan gum (E 418) from its use as a food additive, the exposure was calculated based on (1) maximum reported use levels for food categories in which gellan gum (E 418) is authorised at quantum statis (QS) and maximum permitted levels (MPLs) for the two food categories with numerical maximum levels (defined as the maximum level exposure assessment scenario) and (2) the reported use levels (defined as the refined exposure assessment scenario).

Based on the available data set, the Panel calculated three refined exposure estimates based on different assumptions: a brand‐loyal consumer scenario, a non‐brand‐loyal scenario and the food supplement consumers’ only scenario. The Panel considered that the refined exposure assessment approach resulted in more realistic long‐term exposure estimates compared to the maximum level exposure assessment scenario.

The Panel noted that the estimated long‐term exposures based on the maximum level exposure assessment scenario are very likely conservative, as this scenario assumes that all foods and beverages listed under the annex II to Regulation No 1333/2008 contain gellan gum (E 418) at the MPL or at the maximum reported use levels that were in this case mainly provided from a food additive producer.

For gellan gum (E 418), few reported uses were available on eight food categories. However, not all available data could be included in the assessment owing to specific restrictions/exceptions regarding products not referenced in the FoodEx classification. This may have resulted in an underestimation of exposure to gellan gum (E 418). On the other hand, several food categories for which use data were available were included without considering specific restrictions/exceptions, which may have overestimated the exposure to gellan gum (E 418). In total, 7 out of 71 authorised food categories were taken into account in the refined exposure assessment scenarios. Added to that, approximately 67% of the food products labelled with gellan gum (E 418) in the Mintel’s Global New Products Database (GNPD) belonged to food subcategories that were considered in the refined exposure assessment scenarios (Appendix B).

Several uncertainties were identified in the exposure assessment (Table 5). Overall, for the maximum level exposure scenario, the Panel considered that the uncertainties identified would, in general, result in an overestimation of the exposure to gellan gum (E 418) as a food additive according to Annex II to Regulation (EC) No 1333/2008 in European countries included in the EFSA Comprehensive database. Based on the assumption that the food additive is not used in those food categories in which it is permitted but for which no usage data were provided, also the refined scenario would in general result in an overestimation of exposure.

The Panel noted that the exposure to gellan gum (E 418) from its use according the Annex III (Parts 2, 3, 4 and 5A) was not considered in the exposure assessment.

Since gellan gum (E 418) is authorised and used in a certain type of flavoured drinks, to which consumers may be brand loyal, the Panel selected the refined brand‐loyal scenario as the most relevant exposure scenario for the safety evaluation of this food additive.

Due to the discrepancies observed between the data reported from food industry and Mintel database, where gellan gum (E 418) is labelled in more products than in food categories for which data were reported from industry, the Panel noted that the collection of data on use and use levels of gellan gum (E 418) would allow for a more realistic exposure assessment. The Panel also noted that according to the Mintel’s GNPD, gellan gum was listed as an ingredient in seven products of subcategory ‘growing‐up milk’ (soya‐drink products recommended for young children 1–3 years old) and in five products of subcategory ‘baby juices & drinks’. Gellan gum (E 418) is not authorised as a food additive in those subcategories.

The Panel also noted that the refined exposure estimates are based on reported use levels of gellan gum (E 418). If current practice changes, this refined estimates may no longer be representative and should be updated.

Following the conceptual framework for the risk assessment of certain food additives re‐evaluated under Commission Regulation (EU) No 257/2010 (EFSA, 2014), and given that:

  • from all the data received, data were adequate for a refined exposure assessment for 7 out of 71 food categories;
  • based on the reported use levels, a refined exposure (brand‐loyal scenario) of up to 72.4 mg/kg bw per day in toddlers at the 95th percentile was estimated;
  • gellan gum is unlikely to be absorbed intact and would not be fermented by human intestinal microbiota;
  • adequate toxicity data were available;
  • there was no concern with respect to genotoxicity and carcinogenicity;
  • no adverse effects were reported in chronic studies at the highest doses tested in mice and rats (3,627 and 1,460 mg gellan gum/kg bw per day, respectively).
  • repeated oral intake up to 200 mg/kg bw per day for 3 weeks had no adverse effects in humans,

the Panel concluded that there is no need for a numerical ADI for gellan gum (E 418), and that there is no safety concern at the refined exposure assessment for the reported uses and use levels of gellan gum (E 418) as a food additive.

The Panel recommended the European Commission to consider:

  • changing in the definition of the European Commission specifications the chemical names of the acyl groups ‘glyceryl’ and ‘acetyl’ to ‘glycerate’ and ‘acetate’;
  • indicating in the definition of the European Commission specifications that only the non‐genetically modified strain ATCC 31461 should be used for the production of gellan gum
  • establishing specifications for the individual types of gellan gum with respect to acylation and clarification;
  • including specifications for the absence of viable cells of the microbial source;
  • defining purity in the specifications including the presence of PHB and residual bacterial enzymatic activities;
  • revising the current limits for the toxic elements lead, mercury, cadmium and arsenic in the European Commission specification for gellan gum (E 418) in order to ensure that gellan gum (E 418) as a food additive will not be a significant source of exposure to these toxic elements in food.

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Ria Van Hoef