Is it ok for teen to cook rice at 8am to eat at lunchtime in school? It'll be kept in his school bag

[RiceRiceBabiy]

for 5.5 hours until eaten.
This is regular basmati rice he wants to cook.

He has previously microwaved those packets of rice you can buy in the supermarket and taken those in with no adverse effects.

and yet people in areas of the world that eat rice daily don’t seem to follow these rules so isn’t it interesting to discuss why that might be? In my experience people in the uk don’t wash their rice thoroughly before cooking it, could that be contributing to the number of cases of food poisoning?