Contaminants in food supplements and botanical raw materials
Contaminants
Contaminants play an important role in the marketability of foods, to which dietary supplements belong. But there are not always regulated maximum levels for every food and every contaminant. Especially for botanical raw materials for use in food supplements, which are often highly processed extracts, the assessment of marketability regarding contaminants can be a challenge.
Maximum levels for contaminants in food are laid down in European Regulation (EU) 2023/915. There are a handful of maximum levels in this regulation for the end product of food supplements. These include the maximum levels for heavy metals such as lead, cadmium and mercury, polycyclic aromatic hydrocarbons (PAHs) and, most recently, the maximum levels for pyrrolizidine alkaloids. The maximum levels relate only to the ready-to-use supplements and are not applicable for the individual raw materials.
The EU-Commission is also currently discussing maximum levels for mineral oil aromatic hydrocarbons (MOAH) in food supplements. Various options are currently being evaluated. However, assessing the contaminants in a final supplement regarding the maximum levels is only the last step in the chain. Before that, there is the challenge of assessing the raw materials as marketable for use as an ingredient.
In the Contaminants Regulation, reference is made to the definitions of Regulation 396/2005 for the categories fruits, nuts, vegetables, cereals, oilseeds and spices. For ingredients whose unprocessed form can be found in Annex 1 of Regulation 396/2005 or the EU Pesticides Database, such as acerola powder or artichoke extracts, can then be classified in the corresponding categories of the Contaminants Regulation and, if necessary, assessed using processing factors. If processing factors are used, these must be suitable and reasonable in accordance with Art. 20 of Regulation 2023/915. With extracts, it is important to note that only the processing from the stage, for which the maximum level can be applied directly, to the stage of the extract may be covered by the factor. In other words, if a maximum level already relates to a dried product, the processing factor may only be applied for the process from the dried product to the extract, but not for the process from the fresh plant to the extract.
When it comes to more exotic extracts, for example from ‘Baobab’ (Adansonia digitata), it is much more difficult to categorise the original plant into a maximum level category. Some plants cannot be categorised as described above because sometimes there is no known consumption of this plant other than in food supplements (novel food status: non-novel in food supplements). If, in the example of baobab, it is an extract from the fruit pulp, it can be categorised as authorised novel food and therefore as a processed fruit according to the definition in the Union list of novel foods (Regulation EU 2017/2470). But as soon as other parts of the plant, such as the leaves or roots, are used for the extract, it is classified as a Not-Novel in food supplement and therefore a categorisation according to the Annex of Regulation 396/2005 (e.g. as tea or spice) is questionable.1
So how can you proceed if no specific maximum levels are available? In such cases, the assessment falls back to the stage of the Contaminants Control Regulation (EC 315/93). According to Article 2 of this regulation, the following applies:
- No food may be placed on the market that contains a contaminant in a quantity that is unacceptable from the point of view of health and, in particular, toxicological safety.
- Contaminant levels shall be kept as low as can reasonably be achieved by following good practices.
Therefore, according to this article a risk assessment based on toxicological reference values is necessary: For example, for cadmium or mercury there are TWI values (tolerable weekly intake values). These toxicological reference values can be used to calculate whether a determined content of a contaminant affects the safety of the food or not. The problem with raw materials, however, is that a suitable consumption quantity for the calculation can only be estimated if the exact intended use of the raw material is known. For other contaminants such as PAHs or lead, no toxicological reference values could be defined as these are CMR substances. These are substances that are carcinogenic (C, for cancer), mutagenic (M) or toxic to reproduction (R). No safe dose can be determined for these substances. Therefore, if a maximum level is exceeded for these substances, it is not only a non-marketable food, this is also a non-safe food. If no maximum levels have yet been set for such substances in an applicable category, a final assessment is not possible without a toxicological expert opinion.
One of these CMR substances is arsenic. This contaminant keeps playing a role in food supplements. The Contaminants Regulation sets a row of maximum levels for arsenic in food categories other than food supplements in the range between 0.01 and 0.5 mg/kg. Food supplements containing mainly inorganic salts or synthetic ingredients are particularly difficult to assess regarding inorganic arsenic.
According to the Food Supplements Directive 2002/46/EC, the substances authorised in Annex II must comply with the purity criteria for additives in Regulation 231/2012. Among others, this regulation also specifies maximum levels for arsenic. These are in the range of up to 3 mg/kg.
A content of inorganic arsenic in a food supplement above 3 mg/kg is above any available maximum level in food law and should therefore clearly be considered potentially unsafe. But what about levels between 0.5 and 3 mg/kg? Only a toxicological assessment would be possible here. However, there is no toxicological reference value and therefore a final assessment is again not possible without a toxicological expert opinion.
Whether raw material for food supplements or end product, the assessment of contaminants is never trivial and requires a high level of expertise in food law. As a food business operator, it is essential to be aware of your obligations and to conscientiously keep an eye on possible further contaminants in addition to the specified maximum levels. After all, the food business operator is responsible for the marketability and safety of the food placed on the market.