MOSH and MOAH testing of food and food contact materials – how to ensure safety and compliance?

Reacting to concerns about the adverse health effects of mineral oil aromatic hydrocarbons (MOAH), the EU Standing Committee on Plants, Animals, Food and Feed (SC PAFF) published a report limiting their acceptable concentrations in food in the spring of 2022.¹ The limits outlined in the report took effect immediately, and dozens of products have since been withdrawn or recalled from the market for containing excessive amounts of MOAH.²

The EU is now planning to extend the same limits to mineral oil saturated hydrocarbons (MOSH), another group of potentially harmful mineral oil compounds. While exceeding the limits for MOSH will not lead to product withdrawals, companies are strongly recommended to investigate the causes of contamination and apply appropriate mitigation measures.³

As transfer from food contact materials (FCMs) is one of the main sources of mineral oil contamination, laboratory tests should be performed to measure the migration of MOSH and MOAH from high-risk materials, such as recycled paper and board. The compounds can also be analyzed directly from food products.

What are MOAH and MOSH, and what are the concerns?

Mineral oil hydrocarbons (MOH) are chemical compounds derived mainly from crude oil but also produced synthetically from coal, natural gas, and biomass. Falling under the umbrella of MOH, MOAH and MOSH are specific types of hydrocarbon compounds that have been linked to detrimental health effects. 

In the case of MOAH, the European Food Safety Authority (EFSA) has identified compounds with at least three aromatic rings as genotoxic and carcinogenic. While MOSH compounds have not been found to raise similarly acute health concerns, they do accumulate in the liver, spleen, and other tissues. The long-term effects of MOSH accumulation have not been studied and EFSA considers them to remain uncertain.⁴

Due to the higher toxicological risks, EU regulations and recommendations have thus far been directed primarily at MOAH. However, as continued MOSH accumulation might lead to harmful effects, the EU is also planning to introduce monitoring requirements for MOSH.

What are the EU regulations on MOAH and MOSH?

EU maximum levels for MOAH in food were established in the SC PAFF summary report from April 2022.⁵ The levels are set to match the limits of quantification with currently available measurement techniques, and they vary depending on the fat content of the food: 

• 0.5 mg/kg for dry foods with a low fat/oil content (≤ 4% fat/oil)

• 1 mg/kg for foods with a higher fat/oil content (> 4% fat/oil, ≤50% fat/oil)

• 2 mg/kg for fats and oils (>50% fat/oil)

Discussions are ongoing about incorporating the maximum MOAH levels into EU food contaminant regulations and setting indicative benchmark levels for MOSH. The MOSH levels will be the same, but exceeding them will not lead to immediate product withdrawals, but rather a strong recommendation to investigate the causes.⁶

Which products should be tested?

The maximum and benchmark levels apply to the total amounts of MOSH and MOAH in food regardless of the source, which means that testing is needed across the value chain. 

In terms of finished products, high-risk foods that have been found to contain MOSH and MOAH include vegetable oils, stock cubes, nuts and seeds, cereals, baby food, chocolate products, and dairy. In the food contact material category, the likelihood of MOSH or MOAH being present is higher when the material contains recycled fibers, printing inks, or waxes. Ingredients used in the production process, such as lubricants, greases, and sealants, can also lead to contamination and therefore warrant testing.

How to test for MOSH and MOAH?

General EU guidelines for MOSH and MOAH testing are provided in a Joint Research Centre (JRC) 2023 guidance report, which outlines guidance on sampling and minimum requirements for analytical methods.⁷

MOH analysis is usually performed using LC-GC-FID (liquid and gas chromatography with flame ionization detection). Due to structural similarities, MOH cannot be separated into individual substances using the technique, but MOSH and MOAH components can be distinguished from one another. Further analysis with two-dimensional gas chromatography may be required to confirm the MOAH concentration in cases where naturally occurring substances interfere with the analysis.

Avoiding contamination at all stages of sampling and analysis is important, as mineral oils may unintentionally end up in the sample material from sources like plastic bags and cosmetics. Due to the low detection limit and high risk of contamination, MOSH and MOAH testing requires a high level of expertise from the testing laboratory.

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