EFSA launched a public consultation (1) on its draft scientific opinion on the risks from Mineral Oil Hydrocarbons (MOH) in food, published on March 15, 2023. (2)
Experts from the European Food Safety Authority have provisionally concluded that Mineral Oil Saturated Hydrocarbons (MOSHs) are not a human health problem.
For the other major group of MOHs, known as Mineral Oil Aromatic Hydrocarbons (MOAH) (3) theAuthority states that some may harm health.
Introduction
Mineral oil hydrocarbons contain from 10 to about 50 carbon atoms and are distinguished into MOSH and MOAH based on the saturated simple or aromatic hydrocarbon chains, respectively. They are hydrocarbons derived mainly from crude mineral oil.
MOH can contaminate food in many ways: through environmental pollution, the use of machinery lubricants, release agents, processing aids, food or feed additives, and migration from food contact materials.
Because of their complexity, it has not been possible so far to fully characterize them chemically.
Classification of MOHs
Aliphatic and aromatic hydrocarbons from MOH are distinguished 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 (e.g., 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, may be part of the MOAH fraction.
Hydrocarbons naturally present 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 has asked the European Food Safety Authority (EFSA) to evaluate the toxicity studies on MOH that have become available since EFSA’s 2012 scientific opinion on the subject (4), along with an exposure assessment to update the risk.
The toxicological data set used in EFSA’s 2023 draft opinion is mainly based on studies conducted on MOH derived from crude mineral oils. Data from toxicological studies on 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 MOSHs in foods.
EFSA’s CONTAM scientific panel concluded that MOSHs are not associated with genotoxicity, confirming the conclusions of the 2012 opinion on the absence of carcinogenicity by oral exposure.
He therefore concluded that the risks to human health from current exposure to MOSHs through food are of little concern.
Accumulation of MOSHs in tissues
Accumulation in various tissues with species-specific differences such as liver in a variety of rats was also observed for this category of hydrocarbons.
In the absence of new relevant data, the previous EFSA conclusion that lipogranulomas observed together with MOSH in the liver, spleen, lymph nodes, and other organs in humans are not associated with adverse consequences still holds. In fact, these lipogranulomas differ from the epithelioid granulomas observed in the rats used by the study.
Evaluation of the toxicity of MOSHs to infants
The highest dietary exposure to MOSH has been estimated for the young population, particularly infants. The latter are potentially at greater risk, feeding mainly on milk and infant formula 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 current dietary exposure to MOSH for all age groups is not of concern for human health.
Evaluation of MOAH toxicity
The conclusions of the previous EFSA opinion were also confirmed for MOAH. As in 2012, the opinion reports that there is evidence that some components of MOHs act as tumor promoters following initiation in skin toxicity studies in mice and that some aromatic hydrocarbons, such as naphthalene, act as nongenotoxic carcinogens.
Genotoxicity was mainly associated with the presence of some MOAH with 3 or more aromatic rings.
The alkylation of MOAHs, in fact, could shift the oxidation of the ring to side chain oxidation and alter the position of ring oxidation, thus affecting the ability to form reactive and genotoxic metabolites and carcinogenic potential.
Specifically, fetotoxic effects and on the development of skin toxicity have been observed on DMSO-petroleum extracts enriched in MOAH with 3 or more rings. While no effects were observed in an oral screening study on reproductive and developmental toxicity with a lubricant base oil treated to reduce MOAH to 3 or more rings.
MOAH content in foods
MOAH content in foods and among different age groups was also evaluated. 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 highest dietary exposure to MOAH has been estimated in the young population, particularly infants. The category of ‘Food products for the young population’ is among the major contributors . The main drivers were ‘Follow-on foods, liquid’ and ‘Infant foods, liquid,’ although ‘Ready meals for infants and young children’ was also an important source in several dietary surveys.
Recommendations for further study
Many aspects remain to be investigated for an overall evaluation of MOSHs, including:
- The improvement of analytical methodology for better characterization of MOSHs and more consistent reporting;
- The collection of data on the formation, fate and toxicity of MOSH biotransformation products, including their potential for accumulation. The structural features of MOSH that hinder metabolism and elimination and result in its accumulation remain to be investigated;
- Insight into toxicity in experimental models, particularly on bioaccumulating MOSHs after their characterization. Special attention should be paid to the effects on the liver, spleen, and immune and nervous systems,
- The collection of further data on the possible effects of MOSH on lipoproteins, inflammation, and inflammatory markers,
- in-depth study of tissue concentrations of MOSH in humans or the development and use of biomarkers of exposure , particularly for individuals born after 1995,
- Insight into the contribution from environmental sources, compared with other sources.
Even for MOAH there are aspects that need further investigation mainly lacking data on:
- the composition according to the number of aromatic rings in foods, particularly with regard to MOAH levels of 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, particularly with respect to 1-2 ring MOAHs,
- Updating 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. On the one hand, it is difficult to avoid this source of contamination; on the other hand, the risks may have been underestimated because of the higher propensity for accumulation of predigested MOH.
EFSA’s public consultation (1) on the draft opinion is open until April 30, 2023.
Giulia Pietrollini
Notes
(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 flaws. Ökotest’s investigation – GIFT (Great Italian Food Trade). 11.6.19
(3) Marta Strinati. Tighter limits on MOAH in foods. 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
Graduated in industrial biotechnology and passionate about sustainable development.
