Beyond the visible lesion: mycotoxin attenuation and spatial heterogeneity in maize cobs

Area of Science:

• Agricultural Science
• Food Science
• Mycology

Background:

• Visible mould is commonly used to sort maize, but its reliability in indicating the extent of mycotoxin contamination is uncertain.
• Mycotoxins pose significant risks to human and animal health, necessitating accurate detection and control measures.

Purpose of the Study:

• To investigate mycotoxin attenuation and spatial distribution in relation to visible mould margins on maize cobs.
• To assess the co-occurrence of different mycotoxins within contaminated maize cob sections.

Main Methods:

• Quantification of multiple mycotoxins (FUMs, DON, ZEA, NIV, AFB1) using liquid chromatography tandem mass spectrometry.
• Sampling of maize cob sections at varying distances from visible mould margins (0 mm, 50%, 75%).
• Analysis of mycotoxin levels, spatial heterogeneity, and co-occurrence patterns.

Main Results:

• Visible mould margins contained the majority of mycotoxins (e.g., 84.4% total FUM, 89.4% DON).
• Significant levels of mycotoxins (e.g., 15.6% total FUM, 22.2% ZEA) were found in sections beyond the visible mould.
• DON, ZEA, and NIV decreased with distance, but total FUM did not show significant attenuation; co-contamination was frequent.

Conclusions:

• Visible mould serves as an indicator but not a definitive toxicological boundary for mycotoxin contamination in maize.
• Whole cob rejection or segregation of visibly mouldy maize is a more effective food safety strategy than trimming affected areas.
• Further research into mycotoxin spread and control in maize is warranted.