Mycotoxin concentrations in rice are affected by chalkiness, grain shape, processing type, and grain origin

Area of Science:

• Food Science and Technology
• Public Health and Toxicology
• Agricultural Science

Background:

• Mycotoxins like aflatoxins (AFs), fumonisins (FBs), zearalenone (ZEN), and deoxynivalenol (DON) pose significant public health risks due to carcinogenicity and anti-nutritional effects.
• Sub-optimal food management, control, and regulatory systems exacerbate mycotoxin hazards, particularly in regions like sub-Saharan Africa (SSA).
• Limited data exists on the prevalence of mycotoxins in commercially traded rice within SSA markets.

Purpose of the Study:

• To investigate the occurrence and levels of aflatoxins (AFs) in rice commercialized across markets in five SSA countries.
• To analyze the relationship between grain quality characteristics, processing methods, and origin with AFs contamination.
• To assess the co-occurrence of AFs with other mycotoxins (FBs, ZEN, DON) and compare levels against established maximum limits.

Main Methods:

• Analysis of aflatoxin concentrations in 527 rice samples sourced from 54 markets across five SSA countries.
• Evaluation of grain quality parameters, processing methods, and sample origin in relation to mycotoxin levels.
• Co-occurrence analysis for AFs with FBs, ZEN, and DON in samples exceeding European Union (EU) maximum levels for AFs.

Main Results:

• Aflatoxins (AFs) were detected in 72% of rice samples, with concentrations ranging from 3.0 to 89.8 µg/kg.
• Forty-seven percent of samples exceeded the EU maximum level (ML) of 4 µg/kg for AFs.
• AFs and ZEN co-occurred in 40% of samples; 30% of ZEN-positive samples surpassed the EU ML of 75 µg/kg. AFs did not co-occur with FBs or DON. Slender grains showed significantly higher AFs levels (p < 0.0001).

Conclusions:

• Rice commercialized in SSA markets frequently exhibits high levels of aflatoxins, posing a considerable public health concern.
• Grain quality traits, specifically slender grain morphology, are significant predictors of increased aflatoxin contamination.
• Mitigation strategies should focus on enhancing grain quality, implementing proper drying techniques, and utilizing hermetic storage to reduce mycotoxin risks in rice.