The "clean food" branding is inspired by the success of the "clean energy" branding used by the energy industry, reports Quartz:
By opting for this terminology, the industry hopes to better communicate to people the ethos behind their products, rather than the actual processes (which often do occur in a laboratory) used to deliver them to the kitchen table. It's main selling point: "Clean" meat and dairy are efficient products with fewer sustainability and animal-welfare problems than traditional meat and dairy.
We've got to admit, although it's just a marketing phrase, it already makes food technology products sound more appealing than the previous "cultured" or "lab-grown" terms did. MG