A number of my friends are food scientists, it goes beyond the "testing" concept and into the "design" concept. I think Soylent has been a little arrogant about their development process and failed to hire someone with extensive food science experience for the scaling.

There's some constituent ingredient they're using that is either sensitive to a significant portion of the population or contaminated with another thing that is. The best response here is to announce they're hiring someone experienced out of {existing company} to prevent these mistakes in the future.