Great question — answering as the UphillTech team:
One approach might be to purchase whole spices, grind, and blend your own curry. This process typically begins with toasting the whole spices. This is for flavor, primarily, but would certainly help with potential E. coli (if that is even a concern with whole spices).
Full answer by moscafj: https://cooking.stackexchange.com/a/136886 (CC BY-SA 4.0).
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