What goes for animals also goes for people as you'll see in this article.  Grains for people are just as likely to contain fungi and molds are grains for animal feeds, such as dog food.  Mycotoxins are toxins produced by molds that can affect the health of animals in many ways.  These mycotoxins can be present in hay, pasture, and grain.  Mycotoxins are stable chemical compounds, they are resistant to heating and can remain in the feed for an extended period of time.  It's amazing, this article underscores concerns about animal health that your doctor should be warning you about too.  Oh, your veterinarian hasn't warned you about mycotoxins in your pet food either?