Eating would probably cause a lot of bias thus destroying the randomness. Starting with our taste buds which causes avoidance, the digestion system that will b

Eating would probably cause a lot of bias thus destroying the randomness. Starting with our taste buds which causes avoidance, the digestion system that will break things down so many substances will end up similar despite their differences before hand, and the blood brain barrier which many things can't get past. Then there is dosage, substances can have wildly different effects or none at all depending on how much you give and how long they are given. Dosage would probably be among the bigger issues, if oyster sauce contained a substance that got past those barriers just how much would you have to imbibe to get a positive or negative effect, and would the other ingredients at that level start causing side effects, interference, or otherwise mask the substance.