Aflatoxin accumulation in whole crop maize silage as a result of aerobic exposure.

BACKGROUND: Most of the maize silage stored in horizontal silos is exposed to air and can be spoiled by fungi. Potentially toxigenic fungi have been found inmaize silage, and about 300 mycotoxins have been detected. Among thesemycotoxins, the most harmful for feed and food safety are aflatoxins. The aim of the studywas to set up a specificmethod to detect aflatoxins in maize silage, and to investigatewhether aflatoxin contamination inmaize silage depends on the level of field contamination of the crop, andwhether the occurrence of aerobic spoilage during ensiling has any effect on the final contamination of the silage. RESULTS: A method for the determination of aflatoxin B1, B2, G1 and G2 in maize silage using high-performance liquid chromagraphy with fluorescence detection has been developed and validated. Recoveries of aflatoxin B1, B2, G1, andG2 spiked over the 0.25 to5 ?g kg-1 range averaged 74-94%. The resultsof laboratory scaleandfarmscale ensiling experiments indicated that aflatoxins could increase when silage is exposed to air during conservation or during the feed-out phase. CONCLUSIONS: Themethod here proposed to detect aflatoxins in silages has proved to be sensitive and is able to detect levels of 0.1 and 0.5 ngmL-1 for AFB1 and AFG1, and between 0.025 and 0.125 ng mL-1 for AFB2 and AFG2. This study also provides evidence of aflatoxin accumulation in whole cropmaize silage as a result of aerobic exposure.