Ochratoxin A in wheat: an intercomparison of procedures

Area of Science:

• Food Chemistry
• Analytical Chemistry
• Mycotoxin Analysis

Background:

• Ochratoxin A is a significant food contaminant.
• Accurate analytical methods are crucial for quality control.
• Certified reference materials are needed for method validation.

Purpose of the Study:

• To evaluate methods for ochratoxin A determination in wheat.
• To identify sources of variability in analytical procedures.
• To lay the groundwork for developing certified reference materials.

Main Methods:

• An interlaboratory comparison involving 24 European labs.
• Analysis of naturally contaminated and blank wheat samples.
• Varied extraction solvents (chloroform, methanol, etc.) and clean-up techniques (silica, reversed-phase, immunoaffinity columns).
• High-performance liquid chromatography (HPLC) for determination.

Main Results:

• Recoveries for ochratoxin A ranged widely from 25% to 100%.
• The overall coefficient of variation was 23%.
• Clean-up procedures had a greater impact on result variability than extraction solvents.
• Day-to-day variations and interfering peaks in blank samples were reported.

Conclusions:

• Current methods for ochratoxin A determination in wheat exhibit substantial variability.
• Improvements in clean-up steps are critical for enhancing accuracy and reproducibility.
• Further studies are planned to refine recovery, reproducibility, and investigate matrix effects.