A quick dive into some basic photography knowledge. You'd calibrate to RGB as that's what monitors are comprised of. Typically you'd have to use an external device but the best way without one is http://www.lagom.nl/lcd-test/. However most people don't even have professional monitors so couldn't even calibrate well which makes it's futile. You'd still get a very large variance in color especially from an average joe just eye balling it.
The photo itself has a white piece of paper for white balancing. If I had photoshop, I could color correct it...correctly. The only solution still goes back to a relative comparison. Just buy one of the filaments, a cheap spool of pla pro, and it'll get the job done.
Every food dehydrator I've seen let's you switch but sometimes just doesn't say in the manual. If it's this one that most people post you can switch it by holding the light button. https://www.amazon.com/Septree-Dehydrator-Stainless-Temperature-Protection/dp/B09MCHTXHW