Yes, uncontrolled humidity or temperature are indeed an issue in a flour silo.
Risks - I think the most significant risk is the formation of condensation owing to uncontrolled humidity and temperature resulting in mold growth and mycotoxin formation. Molds can grow at lower moisture than bacteria and the resulting mycotoxins are heat stable so cooking the flour will not remove them. Consumers are therefore at risk of illness from accumulation of these toxins in the body.
Control: Any of the following is generally used to control the humidity and temperature
- Aeration of the silo using fans/blowers - this was what was used at the factory I worked to control heat and humidity in our grain silos. I live in the tropics and the blowers works very well in our silos
- Desiccant Dehumidifiers - I am not familiar with this method but I see it in the research as an option. Maybe someone else here can let you know the advantages and disadvantages