Hi rpsjo and Glenn,
Don't forget that food fraud is more than economically-motivated adulteration (eg. adding water). A potato is a potato, but a conventionally grown potato is cheaper than an organic potato. A Mexican-grown sebago isn't a locally grown sebago. A pesticide-free heirloom variety isn't the same as a conventional, pesticide-treated potato.
Food fraud includes more than just adulteration, and potatoes can be affected. Misrepresentation of geographical origin, organic status and variety are types of fraud that affect vegetables like potatoes.
For example, an investigation in 2018 found that potatoes in Ireland had been fraudulently claimed to be the Queens variety, when they were in fact Accords. (http://www.highlandr...abelling-in-nw/)
In India in 2017, potato traders were accused of covering low quality potatoes with brick dust to sell a poor quality product at a premium price to make quick money http://www.millenniu...potatoes-257456
If I was a potato packer I would want to show my auditor that I had considered the possibility that my suppliers might be providing potatoes that aren't quite true to label. This would be especially important if I was selling 'organic' or 'local' produce.
I hope this helps.