Following the identification of these compounds and their contamination in food, edible oils were recognised years ago to be among the most contaminated by Mineral Oil Hydrocarbons (MOH). Since the 1990s, saturated MOH (MOSH) contamination has been detected in pumpkin seed oil (250 mg/kg of MOH), linseed oil (450 mg/kg), sunflower oil (500 mg/kg) and soybean oil (1000 mg/kg). In 1997, a sunflower oil with 2100 mg/kg was found with saturated MOH. In the following years, a wide range of commercial vegetable oils were found to be contaminated, but the contamination of Ukrainian sunflower oil in 2008 was the most dramatic and led to serious consideration of control measures.

The table below, taken from the European Food Safety Authority (EFSA) report, shows the average MOSH content in different foods, confirming that vegetable oils are quite high compared to other foods.

Tabla de Contaminantes Mosh Moah

Saturated hydrocarbons are an extraordinary family of numerous complex molecules, some of which occur naturally in vegetable oils.

According to research, the main sources of contamination of these compounds are environmental sources (air, soil, and water), the use of lubricants in machines used in production processes, the use of additives in industrial processes and, lastly, migrations from packaging in contact with food. Plants are likely to be contaminated with MOH from the atmosphere through the absorption of gas phase (volatile compounds up to about C24) and the deposition of particulate matter.

According to different articles, there are a variety of routes that influence the assimilation of pollutants by plants, such as contaminated soil, transfer from the soil to the aqueous soil solution and to the air contained in the soil pores, passive and active uptake from the soil solution to the roots, transport from the roots to the stems, through several tissues, xylem vessels, absorption of gaseous compounds from the atmosphere into the plant through leaf stomata, the type of vehicle (with trucks being responsible for most of the paraffins emitted), transport time, etc.    

Some authors claimed that the various machinery used in harvesting, incomplete combustion of diesel and/or the use of lubricating oil may also be a source of MOSH and MOAH contamination.

According to other articles, air pollution with dust and particles with high-in Polycyclic Aromatic Hydrocarbons (PAHs) content could contaminate plants or raw materials through the atmospheric precipitations, and much of this surface contamination could be transferred to the final product. 

Some authors claim that a large amount of foods of plant origin are contaminated with mineral paraffins (up to 300mg/kg in edible oils). This contamination would mostly come from airborne particles, as the molecular size of these paraffins indicates that contamination from soil is much less likely than contamination from air. These authors also state that the most likely sources of these particles are traces of lubricants, residues from incomplete combustion of boilers and diesel, and traces of asphalt and tar from nearby roads or even old trains. 


After several years of studies at Ofade Consulting, and the development of different research projects, it has been confirmed that contamination occurs throughout the entire production process. From the field to the shelf, there are important points of contamination that must be regulated with the most exhaustive control techniques.

The establishment of an exhaustive control process of critical points from the field to the consumer will be the fundamental basis for the eradication of these contaminants.


Ofade has been working with these contaminants in the industry for 15 years and has worked with different methodologies in search of the elimination of these compounds once formed. Ofade has also been in direct contact from the beginning with the main pioneering laboratories in researching a feasible and efficient methodology for the identification of these compounds (Eurofins, SGS) and has followed the evolution of legislation in this area, etc. Due to the important relationship that the company has had since its beginnings with the international vegetal oil sector, the link with MOSH MOA contaminants came to Ofade long before it came to the olive oil sector in Spain. Over the years, the contaminant has become more prominent in the sector and the demands of buyers are starting to worry packers, although the primary producer still does not perceive the concern and the real problem of what is happening. Additionally, the packer has little control over shipments that arrive mixed from an infinite number of farmers, unless they work on good guidance and critical control points for the farmer. 

Despite the lack of clear legislation and certified methodology, the international retail sector has imposed its own internal requirements and is increasingly demanding the limitation of MOSH MOAH in line with published recommendations. It is clear that there is not enough proven toxicity testing on contaminants in humans, that the methodology is not fully certified, and that the legislation is not definitive but instead simply recommends limits, while the customer – in this case the oil buyer – has already imposed their requirements and this PREVAILS in the sale above all else.

Looking away from what is coming will not position us in a global olive oil market, because buyers will go to other markets to look for what they need and if they do not find it, they will go to producers who have taken the decision to eradicate this contaminant and include it in their specifications through the development of a good practice, that will allow them to position themselves at the forefront. The first ones to do so will secure their markets and this will strengthen their market position for years to come. 

For fifteen years, Ofade has been working on the control of this contaminant on a large industrial scale, thus possessing the necessary knowledge to produce EVOOs without MOSH MOAH contamination in large industrial mills and offering their services to help companies in the sector to solve this problem and to be able to enhance their product as a sales and positioning tool in the main markets.