MOAH and MOSH Contamination in Rice:

Mineral Oil Aromatic Hydrocarbons (MOAH) and Mineral Oil Saturated Hydrocarbons (MOSH) are chemical compounds primarily derived from crude oil, and they can find their way into rice through various stages of production, storage, and packaging.

1.  Sources of MOAH and MOSH Contamination in Rice:

Mineral Oil Aromatic Hydrocarbons (MOAH) and Mineral Oil Saturated Hydrocarbons (MOSH) are chemical compounds primarily derived from crude oil, and they can find their way into rice through various stages of production, storage, and packaging.

• Environmental Contamination: Rice crops can absorb MOAH and MOSH from environmental pollutants. Industrial emissions, traffic exhaust, and fossil fuel combustion release mineral oil compounds into the air and soil. Rice, being a crop that absorbs organic compounds from its environment, can take up these contaminants, especially in areas with high industrial activity. Airborne MOAH particles can settle on the rice plants during the growing season, leading to contamination.
• Packaging Materials: One of the significant sources of MOAH in rice is the packaging. Many rice products are packed in recycled paperboard or printed paper, which often contain mineral oil-based inks or adhesives. These materials can release MOAH into rice, especially if there is no inner plastic liner protecting the rice. Studies have shown that rice stored in recycled paper packaging can have higher levels of MOAH compared to rice packaged in new materials.
• Transport and Storage: The use of jute and sisal bags for transporting rice has also been linked to higher MOAH contamination. These bags, often reused for multiple purposes, can carry traces of mineral oils from previous loads, such as petrochemicals or lubricants. The fibers of these bags may also be treated with mineral oils before they are repurposed for rice transport, further increasing the likelihood of contamination.

2.  Health Risks of MOAH and MOSH in Rice

MOAH and MOSH are concerning due to their potential health risks, particularly MOAH, which contains carcinogenic and mutagenic compounds.

• Carcinogenic and Toxic Properties: MOAH fractions, particularly those with three to seven non-alkylated aromatic rings, have been shown to have carcinogenic effects in animal studies. Long-term exposure to these substances, even in low amounts, can accumulate in the body, potentially leading to liver damage, kidney problems, and even cancer. The European Food Safety Authority (EFSA) has raised concerns about the long-term impact of these compounds on human health.
• Health Standards: Although there are no universally established legal limits for MOAH and MOSH in rice, EU regulations recommend a maximum limit of 0.5 mg/kg for dry foods with low fat content (≤ 4%) and 1 mg/kg for foods with higher fat content. This has led to growing scrutiny of rice products, especially those from regions where MOAH contamination is more prevalent.

3.  Analytical Detection of MOAH and MOSH in Rice

To ensure rice is free from harmful levels of MOAH and MOSH, effective analytical methods are crucial.

• LC-GC-FID (Liquid Chromatography-Gas Chromatography-Flame Ionization Detection): This highly sensitive technique is used to detect and quantify both MOSH and MOAH in rice. The LC-GC setup allows for the separation of MOAH and MOSH from other interfering substances, such as paraffin and waxes, which may also be present in the rice. This method is fast, accurate, and can handle large sample volumes, making it ideal for routine analysis in rice processing plants. Quantification involves measuring the peaks corresponding to MOSH and MOAH in different molecular weight regions, providing accurate data on the contamination levels in rice products.
• High Sensitivity and Automation: The combination of liquid chromatography and gas chromatography allows for the high-throughput analysis of rice samples with minimal sample preparation. This is essential for detecting low levels of contamination, which is critical for compliance with food safety standards.

4.  Preventive Measures to Minimize MOAH and MOSH in Rice

Several strategies can help prevent MOAH and MOSH contamination in rice products during production, processing, and storage:

• Packaging Improvements: One of the most significant sources of MOAH contamination in rice is recycled paper-based packaging. To mitigate this, rice producers can use food-grade, non-recycled packaging such as polyethylene or polypropylene bags, which offer a protective barrier against MOAH migration. If recycled paper must be used, it is essential to ensure that rice is double-bagged with a plastic liner to prevent contact with contaminated packaging.
• Monitoring During Milling and Protein Extraction: During rice milling, lubricants and anti-foaming agents used in machinery may contain mineral oils, which can contribute to MOAH contamination. Using food-grade lubricants and enforcing strict cleaning protocols between processing batches can significantly reduce the risk of cross- contamination.
• Reevaluating Transport and Storage Practices: The use of jute or sisal bags for rice storage and transport should be reconsidered. These bags often have higher contamination levels due to previous use for non-food items, like lubricants or petrochemicals. The use of new packaging materials, such as polyethylene bags, can help reduce the risk of MOAH contamination during transport.

5.  Consumer Considerations and Risk Reduction

For consumers concerned about MOAH contamination in rice, there are several measures to reduce exposure:

• Choose Reputable Brands: Opting for rice products from reputable suppliers who follow rigorous food safety standards and regularly test for contaminants like MOAH can minimize exposure. Many manufacturers provide certifications that confirm their products meet maximum MOAH limits.
• Cooking and Heat Treatment: Cooking rice can help reduce the levels of MOAH by up to 50%. While cooking does not entirely eliminate MOAH contamination, it can significantly lower it, especially when the rice is boiled or steamed.
• Proper Storage: Storing rice in cool, dry, airtight containers helps prevent contamination from the environment. Proper storage reduces the chances of MOAH migration during long-term storage and transportation.

6.  Is There Cause for Concern?

Studies have shown that MOAH contamination in rice is widespread, though the levels can vary depending on factors like geography, packaging, and processing methods. For example, a study from the German Federal Institute for Risk Assessment tested 60 rice samples from different regions and found that all of them were contaminated with MOAH. While levels in many samples were below the 0.5 mg/kg threshold, some exceeded these limits, indicating a potential public health concern.

Additionally, research from Italy showed that all 18 rice samples tested contained MOAH, with levels ranging from 0.4 to 2.6 mg/kg. This suggests that, while the levels in some rice may still be acceptable, many rice products are at risk of higher contamination, especially if they come from regions with high industrial pollution or improper packaging.

Conclusion

MOAH and MOSH contamination in rice is a growing concern, especially in products like Brown Rice Protein that are used in dietary supplements, infant formulas, and other food products. While the levels of contamination can vary, studies suggest that environmental pollution, packaging materials, and processing aids are the primary sources of these contaminants in rice.

Preventive measures, including the use of safe packaging materials, monitoring during milling, and routine testing of rice products, can significantly reduce the risk of MOAH contamination. By selecting rice from reliable sources, cooking rice properly, and following storage guidelines, consumers can minimize their exposure to harmful contaminants.

(The below mentioned links are used as a reference for this study)

• http://bit.ly/3AAwXhY
• https://nutraceuticalsgroup.com/fr/news/moah-contamination-in-brown-rice-protein

Published Date: November 12, 2024