Every commercial laundry claims to be hygienic. The ones that mean it can show you exactly how. Here is the standard to hold a vendor to, whatever your sector.
Separation is the foundation
Clean and soiled linen must be kept strictly apart at every stage. This single control prevents the cross-contamination that hygiene is meant to stop.
Right wash, every time
Cycles and chemistry should suit the linen and the risk, applied consistently rather than only when convenient. Consistency is the real measure.
Checked and documented
Every batch should be checked before it leaves, against a documented standard. If a laundry cannot describe its process clearly, that is a warning sign.