The presence of mineral oils in food can cause negative health effects for consumers. The health impacts of the different components of mineral oils vary depending on the fraction extracted:

• MOSH (Mineral Oil Saturated Hydrocarbons):

There are no complete toxicological data for the various MOSH fractions. Some of these highly refined oils are approved as additives in food and food-contact materials. For certain "food-grade paraffin oils," which are characterized by high molecular weight, an Acceptable Daily Intake (ADI) of 12 mg/kg body weight/day has been set. Lower-molecular-weight fractions are of greater toxicological significance.

• MOAH (Mineral Oil Aromatic Hydrocarbons):

Because some highly alkylated aromatic hydrocarbons are potentially carcinogenic, the health risk for consumers is considered high.

What Legislation Defines

There is no European Union law that sets limits for the contamination of food with edible oils. In 2017, the European Commission issued Recommendation 2017/84 on the monitoring of MOSH and MOAH in food, food-contact materials, and articles intended to come into contact with food, in order to collect data on the presence of these contaminants and to evaluate the need for specific measures to protect consumer health.

Germany recently issued its third draft ordinance on mineral oils in food and food-contact materials. This ordinance provides:

• A maximum MOAH contamination of 0.5 mg/kg in food.

• The use of protective packaging materials when contamination from secondary or tertiary packaging is considered likely (for example, cardboard boxes produced with recycled paper).

Due to the absence of EU-wide regulations, some German distributors have set contractual limits for MOSH and MOAH contamination in olive oil.

What the F. CARLI Study Showed in Molai

Confronted with a situation that is not clearly regulated, Fratelli Carli S.p.A. conducted a study on the factors that may cause contamination of olive oil with MOSH and MOAH. At the end of February 2018, sampling and analysis of MOSH and MOAH levels were carried out in the region of Molai. Specifically:

• Olives were sampled directly from the trees before pruning/harvest.

• Samples were taken from olives stored in a PE (polyethylene) sack after harvest, which occurred simultaneously with pruning using a chainsaw lubricated with 100% mineral-oil-based lubricant, harvesting with pneumatic rakes, and the use of plastic nets.

• The safety data sheet of the lubricant used in the chainsaw was examined, and the grower was questioned about the quantity of lubricant oil consumed.

• Olive oil was examined after being produced from the sampled olives at the Molai olive mill.

• Samples of new jute sacks available at a local Molai store were taken.

• A used jute sack from two fields in the area was also sent for analysis.

• Samples were taken from lubricants labeled as "vegetable-based" and free of mineral oils.

• A test was conducted to examine POSH migration from a polyethylene crate (F.lli Carli).

• A sample of a paraffin-based preparation, approved for organic olive cultivation, was sent for testing.

All samples were sent to Eurofins WEJ Contaminants Laboratory in Hamburg, Germany.

Results and Conclusions

• Olives harvested before pruning

They showed no contamination with MOSH or MOAH (levels below the quantification limits: 0.6 mg/kg for MOSH/POSH and 0.15 mg/kg for MOAH).
Field records showed no pesticide application during cultivation.

• Olives sampled from the PE sack

These showed about 5 mg/kg MOSH/POSH and 2 mg/kg MOAH.
This indicates that harvesting and pruning operations cause mineral-oil contamination due to dispersion from the chainsaw lubricant—on both the plants and the harvesting nets. Storage in PE sacks can also increase POSH contamination.

The MOSH/POSH ratio of 2.5 corresponds to typical ratios of "raw" mineral oils not subjected to special refining.

• Olive oil produced from these olives

The extra virgin olive oil showed 20 mg/kg MOSH/POSH and 6.7 mg/kg MOAH.
This experimentally confirms that malaxation concentrates MOSH and MOAH due to the breakdown and migration of these substances during oil production.

MOSH are generally more apolar, so the MOSH/MOAH ratio tends to increase slightly in the oil compared to the olives.

• Amount of lubricant oil contaminating the final olive oil

Approximately 2% of the mineral oil dispersed during harvest contaminates the produced extra virgin oil.
Even though the percentage is low, the resulting MOAH level is far above the desired limit (0.5 mg/kg).

• New jute sacks

They contain very high MOSH (4400–7000 mg/kg) and MOAH (2600–5200 mg/kg).
Thus, they can act as contamination sources for olives stored inside them.

• Used jute sacks

At end of life, MOSH levels were 3250 mg/kg and MOAH 1200 mg/kg.
This decrease results partly from evaporation and subsequent contamination of olives through contact, and partly from environmental dispersion.

Taking into account the life cycle, number of uses, and sack capacity, contamination from jute sacks contributes only minimally to overall olive contamination.

• "Vegetable-based" lubricants

Of the three tested, only one was free of MOSH and MOAH.
One sample had moderate levels (29.5 mg/kg MOSH, 3.5 mg/kg MOAH), unlikely to affect oil contamination significantly.
However, another sample had significant MOSH and MOAH levels, meaning its use should be avoided in place of mineral-oil-based lubricants.