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Ergosterol is a sterol compound of fungi and is produced by fungi and yeast. The concentration of ergosterol is one way determine fungal invasion in grains.

Macri et al. (2003) studied 70 corn samples taken from two years (2001 and 2002) for the presence of ergosterol and zearalenone in Romania. Composite corn samples were taken from different farms. Ergosterol and zearalenone were determined by HPLC (high pressure liquid chromatography).

Ergosterol was detected in all 70-corn samples over the two years. In harvest year 2001, ergosterol content ranged from 0.2 to 72 mg/kg (0.2 to 72 ppm) with a mean of 6.4 ppm. In 2002, ergosterol concentration ranged from 0.2 to 9.7 mg/kg (0.2 to 9.7 ppm) with a mean of 2.1 ppm.

Zearalenone was found in 85% of samples in 2001 and 26% of samples in 2002. Zearalenone content ranged from 4-2250 ppb in 2001 with a mean of 416 ppb. In 2002, zearalenone content ranged from 4 to 192 ppb with a mean of 36 ppb.

The authors indicated that the higher incidence (% samples) and concentrations of ergosterol and zearalenone in 2001 might have been due to the higher rainfall (520 mm v 405 mm in 2002) of that year and unfavorable storage condition during that year. Thus it seems that rainfall and less than optimal storage conditions adversely affect the concentration of ergosterol and zearalenone. We can also see from this research that ergosterol content is indeed a indicator of fungal growth and could be used to predict the presence of potential mycotoxins.

Reference:

Macri, A. M. Schollenberger, Z. Dancea, and W. Drochner. 2003. Zearalenone and ergosterol contents in corn samples of Transylvania, Romania. Mycotoxin Research. 19: 190-193.