Science Snippets!

Maize or corn (Zea mays L.) is typically stored in silos in which grain quality can be monitored and controlled. However, grain is also stored in silo bags---large polyethylene bags that can hold several tons of grain. The grain is put in the bag and then sealed for later use.

Pacin et al (2009) were interested in how fungi, molds and mycotoxins might affect maize quality in silo bags in Argentina. The authors stored grain from 120 to 226 days in 163 silo bags. The bags were closed from April to June and opened from September to November. Pacin et al (2009) measured moisture content, water activity, the presence of molds and yeast, and fumonisin content at the moment of closing and then again at the moment of opening of the silo bags. With this experimental set-up they could determine the effect of time of year on closing and opening of the bags.

The authors found that all silo bags had fumonisin and mold contamination at both closing and opening of the bags. Yeasts were only present in 22 silo bags. Across all dates sampled, the mean fumonisin content at closing was 3079.1 ug/kg (parts per million, ppm) whereas it was 4238.5 ug/kg at opening. Pacin et al (2009) found that bags closed later e.g. in early June, showed higher fumonisin contamination compared to closings in April. Likewise, bags opened later e.g. in November showed higher fumonisin content compared to bag openings in early September. The authors’ data showed no significant effect of the duration of storage on fumonisin content. Pacin et al (2009) conclude that the contamination levels observed at bag opening depend more on the grain quality at the moment of closing than on the storage duration. It would have been interesting if the same experimental set-up was used with conventional grain silos. We could then get a comparison on fumonisin, mold, and yeast content between silos and silo bags.

Reference:
Pacin, A.M., E.C. Bovier, H.H.L. González, E.M. Whitechurch, E.J. Martínez, and S.L. Resnik. 2009. Fungal and fumonisins contamination in Argentine Maize (Zea mays L.) silo bags. J. Agric. Food Chem. 57:2778-2781.

Photo: Courtesy SiloBag®