Sorry, have to call BS on
Maybe it isn't the soy, but I had a 2010 Prius that was loaded with mice all the time, no matter what I tried. Some solutions would last for a while, but the mice always eventually came back to all or part of the car. Got rid of it and got a 2016 Honda CRV. No mice - ever. Same storage location, still plenty of mice around. But none in my car. I even left food in the car, and they still didn't come around. Tons of people on the net complaining about this problem with the Prius. So maybe it wasn't the soy -- I mean, if Ray says so, I'm inclined to believe him. But there is something about the Prius. So, in conclusion ... poor research and bad article.