I hope not. It was meant to be sprinkled on the top after oil and salt has been added. Besides’ we didn’t know that it was toxic. I read about it in my chemistry book and it is available in a medical store.
I am more worried about people keeping insecticides in husked and unhusked rice. Trace amounts of insecticides is very common in grains here. I hope this improves soon since epigenetic changes due to insecticides are very significant.
Update: I looked at wiki after one more comment pointed out toxic nature of kmno4. It wasn’t purple in colour but white. I am definitely recalling the name wrong.
You might be thinking of potassium metabisulphite? [1]
Sounds like it's a white powder, which fits your description. Also, I grew up in India, and am pretty sure that at school, I read about this being introduced to complement traditional preservatives.
I am more worried about people keeping insecticides in husked and unhusked rice. Trace amounts of insecticides is very common in grains here. I hope this improves soon since epigenetic changes due to insecticides are very significant.
Update: I looked at wiki after one more comment pointed out toxic nature of kmno4. It wasn’t purple in colour but white. I am definitely recalling the name wrong.