Like all cereals, oat is commonly (nearly systematically) contaminated by several types of mycotoxin (produced by molds) known to cause cancer{1}. Oat is one of the most infected cereals{2}. Unless the package looks or smells bad (which is unlikely, and even dangerous to touch since some mycotoxin can penetrate through the skin), there is no way to know its level of toxicity.{3} Eating a large quantity of oatmeal (eg 250g/day) could thus be problematic, especially in a country that doesn't take this kind of food contamination seriously (even if the customer store the oats in a dry environment, it's too late: the molds have already grown (eg. while stored in a humid silo or warehouse, or during transportation).
There isn't much information about how to reduce mycotoxin in oat specifically but some studies done on other cereals suggest some procedures:
"Heating and cooking under pressure can destroy nearly 70% of aflatoxin in rice compared to under atmospheric pressure only 50% destroyed (37)".{4}
According to several studies, mycotoxins can be totally eliminated by cooking it at 160-180°C for 30 minutes {5}. But it doesn't make sens "Since [...] long-time cooking and overheating would destruct essential vitamins and amino acids in treated food".{4} (And it would not be easy to do: is it possible to reach such temperature in a pot ? Won't it burn? Plus this is quite an energy-intensive process and thus not ecologically responsible nor economically interesting).
Another study{6} mentions a more practical option: they reduced the quantity of mycotoxins (till 70-87%) by adding sodium bicarbonate. The study focuses on corn: they add 9 gr of sodium bicarbonate per liter. But the paper doesn't describe well the procedure: they wrote "the results obtained in this work correspond to an aqueous solution", which suggest they mixed some water, the corn (as flour?) and the sodium bicarbonate, but what quantity of water/corn, what temperature and for how long...?
And these pieces of information don't provide a practical way to reduce the mycotoxins in oats : Oats aren't cooked like rice which needs to stay 10 (or more) minutes in boiling water. To cook oat, I simply pour boiling water on it and wait 15 min. It probably doesn't reduce much the aflatoxin (how many percent?). What about adding bicarbonate with the boiling water? (how many percent reduction?)
Is there a better way, or other steps that would decrease the amount of mycotoxins in oatmeal?
1:
https://www.tandfonline.com/doi/abs/10.3109/15569541003598553?journalCode=itxr20
2: https://www.sciencedirect.com/science/article/abs/pii/S2214799317300152
3: Aflatoxin is colorless and completely invisible. The loss of the nuts smell, which happens when the oats start to turn bad (just before they start to smell and then taste bad) is probably the only indication our senses can detect.
4: http://www.fao.org/3/x5036e/x5036e0q.htm
5 https://link.springer.com/article/10.1007%2FBF03032339
6: https://onlinelibrary.wiley.com/doi/abs/10.1002/jsfa.11001