EFSA has launched a public consultation (1) on the draft scientific opinion on the hydrocarbon risks of mineral oils (MOH, Mineral Oil Hydrocarbons) in food, released March 15, 2023. (2)
Experts from the European Food Safety Authority have provisionally concluded that saturated hydrocarbons from mineral oils (MOSH, Mineral Oil Saturated Hydrocarbons) do not constitute a problem for human health.
For the other major group of MOHs, known as mineral oil aromatic hydrocarbons (MOAH, Mineral Oil Aromatic Hydrocarbons) (3) the'Authority states that some can be harmful to health.
The hydrocarbons mineral oils contain from 10 to about 50 carbon atoms and are divided into MOSH and MOAH based on the simple or aromatic saturated hydrocarbon chains respectively. They are hydrocarbons derived primarily from crude mineral oil.
I MOHs can contaminate food in many ways: through environmental pollution, the use of machine lubricants, release agents, processing aids, food or feed additives, and migration from food contact materials.
Due to their complexity, it has not been possible so far to characterize them chemically in a complete way.
Classification of MOHs
The hydrocarbons aliphatic and aromatic from MOH are divided into saturated mineral oils (MOSH) and aromatic hydrocarbons from mineral oil (MOAH).
In this opinion, the term MOH includes:
- mineral oils and waxes obtained from crude oils by chemical fractionation and refining processes (for example, cracking or hydrogenation);
- oils and waxes produced by Fischer-Tropsch synthesis using coal, methane or biomass as sources, also known as gas-to-liquid (GTL) oils;
- heterocyclic compounds, mainly thiophenes, can be part of the MOAH fraction.
The hydrocarbons naturally occurring as components of foods, as well as other hydrocarbons from different sources, such as plastics, are not included in the definition of MOH.
EFSA's new opinion on MOHs
The European Commission requested the European Food Safety Authority (EFSA) to evaluate the toxicity studies on MOH that have become available since EFSA's scientific opinion on the matter in 2012 (4), together with an exposure assessment allowing to update the risk.
The set of data Toxicological assessments used in EFSA's 2023 draft opinion are mainly based on studies carried out on MOHs derived from crude mineral oils. Data from toxicological studies of GTL products were also considered as supporting information, although there are limitations, as GTL oils do not have the same composition as mineral oils.
Evaluation of the toxicity of MOSH in food
The scientific group EFSA's CONTAM concluded that MOSHs are not associated with genotoxicity, confirming the conclusions of the 2012 opinion on the absence of carcinogenicity by oral exposure.
So he concluded that the risks to human health from current exposure to MOSH through food are of little concern.
MOSH accumulation in tissues
For this category Hydrocarbon accumulation was also observed in various tissues with species-specific differences such as liver in a variety of rats.
In the absence of new data relevant, the previous EFSA conclusion that lipogranulomas observed together with MOSH in human liver, spleen, lymph nodes and other organs are not associated with adverse consequences still holds. These lipogranulomas in fact differ from the epithelioid granulomas observed in the rats used in the study.
Evaluation of the toxicity of MOSH for newborns
The exposure higher food intake at the MOSH was estimated for the young population, especially for infants. The latter are potentially at greater risk, feeding mainly on milk and infant products, among the products mainly contributing to MOSH.
However, considering the short duration of exposure through infant formula, MOHs are of no concern. Overall, EFSA concluded that the current dietary exposure to MOSH for all age groups does not raise concerns for human health.
Evaluation of the toxicity of MOAH
Also for MOAH the conclusions of the previous EFSA opinion were confirmed. As in 2012 the opinion reports that there is evidence that some components of MOHs act as tumor promoters following initiation in mouse dermal toxicity studies and that some aromatic hydrocarbons, such as naphthalene, act as non-genotoxic carcinogens.
Genotoxicity has been mainly associated with the presence of some MOAH with 3 or more aromatic rings.
The alkylation Indeed, MOAH could shift ring oxidation towards side chain oxidation and alter the position of ring oxidation, thereby affecting the ability to form reactive and genotoxic metabolites and carcinogenic potential.
In particular Foetotoxic and developmental skin toxicity effects were observed on DMSO-petroleum extracts enriched in 3 or more ring MOAH. While no effects were seen in one study by screening methods oral reproductive and developmental toxicity report with a lubricating base oil treated to reduce MOAH to 3 or more rings.
MOAH content in foods
It has also been evaluated the MOAH content in foods and among different age groups. It was found that the food groups with the highest average contribution of MOAH are the categories of:
- cereals and cereal products,
- animal and vegetable fats and oils and their primary derivatives,
- oils and their primary derivatives,
- coffee, cocoa, tea and infusions.
The exposure higher MOAH has been estimated in the young population, particularly in infants. The category of 'Food products for the young population' is among the main contributors. The main driving factors were 'follow-on formula, liquid' e 'Infant formula, liquid', although also 'Ready meals for infants and children' has been an important source in several dietary surveys.
Recommendations for further reading
remain still many aspects to be explored for an overall evaluation of the MOSH, including:
- improved analytical methodology for better characterization of MOSHs and greater reporting consistency;
- the collection of data on the formation, fate and toxicity of MOSH biotransformation products, including their potential for accumulation. The structural characteristics of MOSH that hinder its metabolism and elimination and determine its accumulation remain to be investigated;
- study on toxicity in experimental models, in particular on bioaccumulative MOSHs after their characterization. Particular attention should be paid to effects on the liver, spleen, immune and nervous systems,
- the collection of further data on the possible effects of MOSH on lipoproteins, inflammation and inflammatory markers,
- insight into human tissue concentrations of MOSH or the development and use of biomarkers of exposure, particularly for individuals born after 1995,
- insight into the contribution from environmental sources, compared to other sources.
Also for MOAH there are aspects that need further investigation mainly lack of data on:
- the composition according to the number of aromatic rings in foods, in particular with regard to the levels of MOAH at 3 or more rings,
- sources of food contamination should be investigated when MOAH are detected. To this end, more selective and sensitive analytical methods are needed,
- the influence of ring alkylation on the genotoxicity and carcinogenicity of MOAHs with 3 or more rings,
- oral toxicity, especially for 1-2 ring MOAH,
- the update of the technical specifications of white mineral oils and waxes used as food additives and food packaging materials, with information on the content and composition of MOAH.
- the contribution of the environment. While this source of contamination is difficult to avoid, the risks may have been underestimated due to the increased propensity for accumulation of predigested MOHs.
The consultation public opinion (1) on the draft opinion is open until 30 April 2023.
(1) Public Consultation on the draft scientific opinion on the update of the risk assessment of mineral oil hydrocarbons in food. PC-0400. EFSA. 15.3.23 https://connect.efsa.europa.eu/RM/s/publicconsultation2/a0l09000006qqHf/pc0400
(2) Dario Dongo and Marina De Nobili. Extra virgin olive oil, dangers and defects. The Ökotest investigation - GIFT (Great Italian Food Trade). 11.6.19
(3) Martha Strinati. Tighter limits on MOAHs in food. GIFT (Great Italian Food Trade). 31.5.2022
(4) EFSA Panel on Contaminants in the Food Chain (CONTAM). Scientific Opinion on Mineral Oil Hydrocarbons in Food. EFSA journal. Vol 10 https://doi.org/10.2903/j.efsa.2012.2704 6.6.12