Iris Eckstein, Magdalena Lubecki, Dr. Uwe Lauber
In 2014 kitchen utensils and tableware apparently made of bamboo and corn starch attracted attention for their claims of being especially ecological and environmentally friendly. Unspoken by the producers, however, was the fact that synthetic materials such as melamine and polylactic acid were used during production. The specific migration limit for melamine was exceeded in three of the four samples analyzed. All of the products were judged as unmarketable due to, among other reasons, deceptive labels. Import regulations for consumer goods made of melamine aren't effective because the products are presumably not being legally registered with the customs authority as synthetic kitchen articles containing melamine.
Bamboo (Rio Tambopata, Peru).
Promotional leaflets and packaging contain assertions that these products are made from a mixture of ground bamboo and cornstarch, bonded with resin. These articles are offered in a wide variety of shapes and colors on the market. The matte, often uneven surfaces make the plastics used in manufacturing difficult to recognize. This impression is reinforced by corresponding advertisements, which purport to suggest that the objects are made of natural products (mostly bamboo) alone. The products are distributed Europe-wide, from various online suppliers as well as special shops, including so-called world shops.
In the last two years a total of 13 samples of so-called bamboo dishware from six different distributors were analyzed. The current series of tests involved six products from five different companies. Melamine resin was detected in 11 of the 13 samples; two of the samples were found to contain polylactic acid (PLA), presumably for its structure-providing properties. All of the samples that were presented for analysis were thus found to contain plastic.
Advertisements for a wide variety of "bamboo" products from various suppliers accentuate that they are, for example, an alternative to melamine and up to 100% natural. Our results present a different picture. Individual samples only contained 20 – 37% bamboo, whereas these goods contained a high percentage of plastic. Four of the six currently analyzed samples contained melamine (see Info Box).
Melamine resins are polymers consisting of the elements (monomers) melamine and formaldehyde. Melamine resins are very hard, so they are often used in the manufacturing of kitchen utensils such as plates, bowls, cups and cutlery. The problem with this material lies in the fact that the monomers melamine and formaldehyde that aren't fully converted during production can be transferred into food. This is especially problematic for products that come in contact with heat (coffee cups, soup bowls, spatulas). (Römpp, Chemical Lexicon)
The consumer is not informed that these products contain any plastic. In fact, one particular product we analyzed was advertised as being an "alternative to melamine", while containing melamine itself. All analyzed products were therefore judged as deceptive and not marketable.
Investigations of melamine-containing samples with regard to a possible release of melamine revealed that the specific migration limit had been exceeded (see Info Box). The amount of melamine detected was over the legally acceptable level of 2.5 mg/kg, within the margin of error, in three out of four samples.
The specific migration limit value is the maximum amount of a particular substance that is permitted in food. This value should ensure that the food contact material poses no health risk. The manufacturer must ensure that materials and objects that have not yet come in contact with food nevertheless adhere to this maximum limit. This acts as a safeguard against the worst foreseeable situation that would bring food in contact with such materials.
The remaining two of the six samples were found to have been manufactured with polylactate (PLA) instead of melamine. They contained an average of 34% bamboo.
Polylactates are polyesters derived from lactic acid. Polylactic acid can be so manufactured that it is biodegradable and can be used, among other things, as resorbable surgical suture material. (Römpp, Chemical-Lexicon)
For both products containing PLA, a migration analysis (after 2 hours, at 70°C with 3% acetic acid) showed that the food contact surface had changed after treatment (see photo). We deem them, as such, inappropriate for use with warm or sour foods such as coffee, fruit tea or fruit compote because these changes could also affect the food. According to the manufacturer, however, the use of these products is not limited to certain conditions.
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Condition of food contact surface after migration. |
Normal household use of kitchenware is simulated with test media (e.g. 3% acetic acid, 0.5% citric acid, 10–50% ethanol or plant-based oil) that simulate food (sour, alcoholic or fatty food). This simulation imitates the migration of substances from food contact materials into food. Depending on the range of use, the objects are tested after, e.g. 15 to 120 minutes at temperatures of 70–100°C.
Polylactates are also referred to as bioplastics because they're made from renewable raw materials. The manufacturing of PLA involves the fermentation of corn into lactic acid, which then undergoes a polymerization reaction and cleansing. The terms bioplastic, biopolymer and organic-based are still not clearly defined, however. For example, the term bioplastic does not necessarily mean that the plastic is biodegradable. It can be biodegradable, but doesn't have to be.
These plastics mustn't necessarily be produced from renewable plant or animal-based raw materials. Biodegradable plastics can also be produced from fossils, a non-renewable resource.
In the current series of investigations emphasis was placed on the use of renewable raw materials (bamboo, cornstarch or, e.g. lactic acid, which is extracted from the fermentation of corn) and their biodegradability.
Polylactic acid is also found in connection with synthetic plastics! Their actual degradability depends on the manufacturing process. The given time frame of 12 to 24 months in which the product should be fully degraded must therefore be scrutinized. This is especially necessary for the biodegradability of products containing melamine.
Compostable Garbage Sack.
In our estimation, these products are subject to the regulations of the European ordinance for plastics. This also follows for the declaration of compliance of some individual cases currently under our investigation, the products for which are categorized, also by the manufacturer, as being made of plastic.
To our knowledge, a filler of pulverized bamboo and cornmeal is applied to this synthetic material.
The structure of the products (shape and firmness) is achieved by the plastic, not by the filler. Consequently, in addition to a declaration of compliance, it is required to present supporting documents (e.g., analysis certificates).
Analyzed Samples.
In addition, the following explanation is given for the guidelines in commission regulation (EU) Nr. 10/2011: "Included in the plastics ordinance are organic-based and biodegradable plastics, as long as they are made of synthetic polymers, chemically changed natural or synthetic polymers or polymers that are extracted via microbial fermentation." In our opinion, products containing the so-called bioplastic polylactate (PLA) are therewith included in the plastics ordinance.
Regulation (EU) Nr. 284/2011 was enacted in July 2011 and is valid for kitchen utensils; it contains special conditions and detailed procedures for the importation of plastic kitchen articles made of melamine from China and Hong Kong, China.
The manufacturing of these said products takes place, to our knowledge, mainly in China. However, it is assumed that they don't enter the EU with the appropriate customs code of "plastic kitchen article". Moreover, there seems to be no hint as to the actual material composition of the products, making it difficult for the customs authorities to identify articles that are subject to declaration.
All of the products were determined to be unmarketable for the following reasons (depending on the product, individually or in combination):
The above-mentioned products were offered mainly online and in retail shops, with claims of being, among others, environmentally friendly, safe, natural and long lasting. Individual products were promoted as being an alternative to melamine dishware, although they themselves contained a large amount of melamine resin. This is a clear case of consumer fraud.
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