Why do sprouts sometime get negative press? What pro-active measures can home sprouters take to avoid bad sprouts?
Growing sprouts is like growing a baby, which doubles its weight in 6 months. As it metabolizes it creates a lot of waste (just ask anyone who has changed diapers!) But with sprouts, it is like an eight pound baby growing in just seven days into a 128 pound baby! A LOT of energy is expended in the process, with heat and a bio-film as by-products. Because heat is produced sprouts must be cooled down at least twice a day with cold water or spoilage will occur. The bio film produced is natural waste, and this needs to be rinsed away.
Sprouts also require adequate ventilation to help keep them cool, but not so much that they get dried out.
Another aspect of sprouting which requires vigilance is sanitization. If care is not taken to sanitize equipment then bacteria can grow, because bacteria likes to thrive in warm, moist environments. Seeds also need to be sanitized, as all seed naturally has bacteria on the outside.
Finally, as mentioned, high quality seed needs to be used to avoid spoilage. Reputable sprouting seed suppliers have their seed constantly tested by an independent source to ensure there are no pathogens or microbes.
So there are a few points at which spoilage or contamination can occur, but that is all preventable when care is taken. To determine if there is a problem, look for stunted shoot growth, brown-looking roots which are slimy to the touch, and a rotten smell. "If in doubt, throw it out".