Sources of Mineral Oil Contamination in Food
Mineral oil can enter the food supply chain at multiple points, and contamination is often unintentional. It is important to distinguish between this type of contamination and the intentional use of highly refined, food-grade mineral oil for specific purposes.
Migration from Food Packaging
One of the most common sources of mineral oil contamination is migration from food packaging, particularly from recycled paperboard. Printing inks used on recycled materials often contain mineral oil hydrocarbons (MOH) which can evaporate and transfer to dry food products inside the packaging. This is especially problematic for items stored for long periods. Manufacturers often use a 'functional barrier' layer to prevent this migration, but its effectiveness can vary.
Machinery Lubricants and Processing Aids
In food processing plants, equipment like conveyors, mixers, and cutting machinery require lubrication to function correctly. If industrial-grade lubricants containing mineral oil are used and come into contact with food, contamination can occur. To prevent this, facilities are supposed to use highly refined, food-grade lubricants, but improper practices can lead to accidental exposure. Food-grade mineral oil is also used intentionally as a release agent to prevent food from sticking to equipment, particularly in bakeries.
Environmental and Agricultural Contamination
Mineral oil hydrocarbons can also enter the food chain through broader environmental pathways. This includes:
- Agricultural use: Some pesticides use mineral oil as an ingredient, which can lead to residue on crops.
- Transport: Transporting raw ingredients in oiled jute bags or other containers that have been in contact with mineral oil can cause contamination.
- Pollution: Fish and other seafood can be exposed to mineral oil from ocean pollution, which can then enter the human food chain.
Foods Susceptible to Mineral Oil
Based on findings from organizations like the European Food Safety Authority (EFSA) and consumer groups, several food categories are known to contain or be at risk of mineral oil contamination.
- Cereals and Grains: This includes rice, pasta, breakfast cereals, and cereal-based products. Contamination often occurs from recycled cardboard packaging or from processing equipment lubricants.
- Chocolate and Confectionery: Mineral oil can migrate into chocolate products from their packaging. Additionally, food-grade mineral oil is sometimes used as a glossing agent or to prevent candy pieces like Swedish Fish from sticking together.
- Vegetable Oils and Fats: Contamination can occur during the processing and handling of vegetable oils, and unfortunately, food fraud involving the adulteration of edible oils with mineral oil has also been reported.
- Processed and Packaged Foods: Many processed meals, snacks, and ready-to-eat salads are at risk of contamination through packaging or machinery contact.
- Baby Food and Infant Formula: Of particular concern is the potential for MOAH (Mineral Oil Aromatic Hydrocarbons) in baby milk powder, which has prompted specific monitoring and regulations.
The Mineral Oil Spectrum: MOSH vs. MOAH
When discussing mineral oil hydrocarbons (MOH), it's important to understand the two main classifications based on chemical structure, as they have different health implications.
What are MOSH?
MOSH, or Mineral Oil Saturated Hydrocarbons, are saturated hydrocarbons derived from mineral oil. They consist of branched and unbranched carbon chains. The primary health concern with MOSH is that they can accumulate in human tissue over time, particularly in the liver, though the risk at current dietary exposure levels is generally considered low. Regulatory bodies still advise keeping MOSH levels in food as low as reasonably achievable.
What are MOAH?
MOAH, or Mineral Oil Aromatic Hydrocarbons, are aromatic hydrocarbons with ring-like structures. Some MOAH compounds are considered potentially mutagenic and carcinogenic, meaning they could damage DNA and potentially cause cancer. For this reason, regulatory and consumer advocacy groups call for a zero-tolerance policy for MOAH in food, especially products for infants.
Comparison: Food-Grade vs. Industrial Mineral Oil
| Feature | Food-Grade Mineral Oil | Industrial Mineral Oil |
|---|---|---|
| Refinement | Highly refined and purified to remove contaminants like MOAH. | Minimally refined and may contain a wider range of impurities. |
| Safety | Considered 'Generally Recognized as Safe' (GRAS) for incidental contact in small amounts. | Not safe for consumption and may contain toxic additives. |
| Primary Use | Lubricant for food machinery, release agent in baking, coating for fruits/confectionery. | Lubricant for engines, hydraulic systems, and other non-food industrial applications. |
| Purity | Meets strict safety standards set by regulatory agencies like the FDA and EFSA. | Does not meet food safety standards and is not monitored for food contact safety. |
Understanding the Labels and Regulations
As there are currently no universal legal limits for mineral oil hydrocarbons in all foods, relying solely on labels can be misleading. Contamination often occurs unintentionally and is not listed as an ingredient. However, in regions like the EU, guidance is being developed to reduce MOH levels, and for sensitive products like infant formula, stricter limits on MOAH are in place. Consumers can stay informed by following organizations like foodwatch, which advocates for stricter regulations and regularly tests products. You can find more information about mineral oil contaminants in food from the European Food Safety Authority (EFSA).
Conclusion
While food-grade mineral oil is intentionally used in small, regulated quantities for certain products, the primary concern for consumers is unintentional contamination from sources like packaging and machinery lubricants. Cereals, chocolate, and other processed and packaged foods are particularly susceptible to this issue. The key distinction between saturated (MOSH) and aromatic (MOAH) mineral oil hydrocarbons is critical, given that MOAHs are considered potentially carcinogenic. Efforts by consumer groups and regulatory bodies are pushing for more transparent practices and stricter limits to minimize human exposure. While eliminating mineral oil entirely from the food chain is a complex challenge, awareness of the primary sources can empower consumers to make more informed purchasing decisions.
