Determining the variability associated with testing shelled corn for aflatoxin using different analytical procedures...

Area of Science:

• Agricultural Chemistry
• Food Safety
• Analytical Chemistry

Background:

• On-site testing for aflatoxin in shelled corn at elevator facilities is increasing.
• Accurate aflatoxin determination is critical for corn quality and safety, especially in high-throughput environments.
• Variability in testing can lead to significant implications for the grain industry.

Purpose of the Study:

• To compare aflatoxin test results between elevator laboratories and a central laboratory (Louisiana Agricultural Chemistry - LAC).
• To assess the variability in aflatoxin testing due to sampling, sample preparation, and analysis at elevator locations.
• To identify sources of error in on-site aflatoxin testing of shelled corn.

Main Methods:

• Analyzed 100 lots of shelled corn from 10 Louisiana elevators.
• Used the Aflatest method for on-site testing at elevators and at the LAC laboratory.
• Employed high-performance column liquid chromatography (HPLC) at the LAC laboratory for comparative analysis.

Main Results:

• Elevator laboratories reported significantly lower mean aflatoxin levels (P < 0.05) than the LAC laboratory using the Aflatest method.
• Aflatest method results were generally lower than HPLC results.
• Sampling and sample preparation accounted for approximately 91.5% of the total variability in testing, while the analytical step contributed only 8.5%.

Conclusions:

• Differences in aflatoxin testing results may stem from analyst technique, attention to detail in busy settings, or facility limitations at elevators.
• Sampling and sample preparation are the primary drivers of variability in shelled corn aflatoxin analysis.
• Improving sampling and sample preparation protocols is crucial for enhancing the accuracy of on-site aflatoxin testing.