Is Anthraquinone safety as food packaging substances?

Anthraquinone, also called anthracenedione or dioxoanthracene, is an aromatic organic compound with formula C14H8O2. The CAS NO of Anthraquinone is 84-65-1. Several isomers are possible, each of which can be viewed as a quinone derivative. The term anthraquinone, however, almost invariably refers to one specific isomer, 9,10-anthraquinone (IUPAC: 9,10-dioxoanthracene) wherein the keto groups are located on the central ring. 

It is a building block of many dyes and is used in bleaching pulp for papermaking. It is a yellow highly crystalline solid, poorly soluble in water but soluble in hot organic solvents. For instance, it is almost completely insoluble in ethanol near room temperature but 2.25 g will dissolve in 100 g of boiling ethanol.

Fears about food contact material anthraquinone’s carcinogenic properties have prompted Germany’s Federal Institute for Risk Assessment (BfR) to drop it from its recommended list for food packaging substances.

It believes Anthraquinone(CAS NO:84-65-1), which is used in the production of pesticides, and paper and cardboard, including that used for food packaging, could exceed recommended safe levels in some foods. The organisation singles out pizza as one area of concern in a statement on the substance. It aims to lobby for a consistent view on the health hazard posed by anthraquinone, which is also used in paper, cardboard and paperboard for baking, under European chemicals (REACH) legislation.

Carcinogenic potential

Since the substance has been shown to be carcinogenic in animal experiments, anthraquinone may have carcinogenic potential for humans as well, states the risk assessment body. For this reason, the BfR cannot continue to recommend the use of anthraquinone as an accelerator for the separation of lignin and cellulose in the extraction of cellulose fibre [a process used during paper and cardboard manufacture]. The BfR was basing its comments on an opinion paper issued last year by the European Food Safety Authority (EFSA).

Hazard potential cannot be determined

In its opinion on anthraquinone as an active pesticide ingredient, the EFSA concludes that carcinogenic effects cannot be ruled out for anthraquinone and that the hazard potential for mammals cannot be determined unequivocally.

Animal experiments show that anthraquinone can have a carcinogenic effect on the kidneys and liver. The International Association for Research and Cancer (IARC) classifies the substance as a possible carcinogen for humans (group 2B). As a pesticide residue, no safe level has been set specifically for anthraquinone in food, so a maximum default level of 0.01mg/kg applies, according to Article 18(1)(b) of EC Regulation 396/2005. That said, the EFSA opinion paper was unable to establish whether that limit sufficiently protected consumers.

Can exceed permitted residue limit

But the BfR states: The BfR has estimated that anthraquinone contamination from paper and cardboard can exceed the permitted residue limit. In addition, the BfR has information on cases where the permitted residue limit value for anthraquinone was exceeded in tea which can be attributed to the anthraquinone levels contained in the paper and cardboard used as packaging materials. Assuming the maximum permitted level of anthraquinone in paper and cardboard of 30mg/kg, the organisation claims it could appear in foods packaged in them in levels up to 0.45mg/kg.

Pizza 

Test results from the National Council for Air and Steam Improvement show that during storage, pizza absorbs up to 5% of the anthraquinone in a pizza carton, the BfR states. Based on these, it calculates pizza could absorb up to 0.04mg/kg of anthraquinone, above the recommended limit. A two-year National Toxicology Feeding Programme feeding study on rats and mice exposed to anthraquinone in 2005 reported increased abnormal tissue growth in the kidneys of female rats. Similar effects were also observed in male and female mice. The IARC claims there is inadequate evidence that anthraquinone is carcinogenic in humans, but sufficient evidence that it is in experimental animals.

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