I don't know what you mean by spoiled?  If they are in the mix, they are being converted~fermented~by the metabolic processes of the beneficial bacteria found there. The cloudiness of the fluid is more from the flour dust off of grains than anything else and also the starches/sugars being changed in the fermentation process, but is still good.
 
To be fair, fermentation is a type of rotting, or spoiling, of the food..just a controlled spoiling that doesn't involve harmful pathogens as the beneficial pathogens are being fed their favorite foods and are being colonized in greater numbers.  If one were to leave that bucket alone to fend for itself..eventually the mix would grow dryer, the available nutrients that the LAB feed off of would be used up, all the alcohol sugars would be consumed by the vinegar bacilli, and they would all die...leaving what remains to the more harmful bacteria/molds to grow stronger and take over and the feed would truly be spoiled then. 
 
As long as the beneficial bacteria are being fed and cared for, their sheer numbers and the chemicals released by their metabolism prohibit the growth and overgrowth of harmful bacteria/molds. 
 
To feed and care for them is easy...add fresh feed, keep them moist.