Rice was the most common form of food poisoning in the UK for a while. Cooling the rice takes it through bacteria reproduction temperature; as does reheating the rice. The bacteria don't cause the poisoning though, so killing them doesn't help. The bacteria release a toxin and that isn't destroyed by heating.

So, if people are going to try this they need to cool the rice down as quickly as possible; keep it cold; and then properly reheat it.

http://www.nhs.uk/chq/Pages/can-reheating-rice-cause-food-po...