> recent literature searches have put me off a bit, given that brittle ceramic blades like Zirconium oxide shed sharp microparticles that I doubt are good for the ingester

so you fear harmful microparticles, so instead you suggest something normal, like

> steel blade overcoated with a thin Teflon layer

eh?? isn't teflon that scary(tm) substance you must never scratch off your pan or you'll poison yourself?

how's that any better than zirconium?