Can a humid storage environment of surgical instruments before reprocessing increase patient safety and durability of instruments?

National and international guidelines recommend reprocessing of medical instruments to commence as soon as possible post-surgery; furthermore, they recommend that transport and storage of surgical instruments postoperatively occurs in a moist, humid atmosphere. The concern is that a dry storage environment results in deterioration of instruments. To evaluate whether residual protein or corrosion is associated with storage environment (dry or humid), holding time or number of treatment cycles. The range of protein residue and corrosion were tested on surgical instruments contaminated with human blood amended Enterococcus faecalis ATCC 29212. Subsequently instruments were stored for 6, 12 and 24 h in dry or humid conditions. After one, 25 and 50 reprocessing cycles, instruments were examined for protein residues using the o-phthaldialdehyde (OPA) method or corrosion using stereomicroscopy, scanning electron microscopy and energy dispersive spectroscopy. Protein residue found on instruments was 21.5–54.0 μg and corrosion corresponded to 0–5% of the inspected area. No associations between storage environment and protein residue (adjusted mean difference = 0.48, 95% confidence interval: -0.42, 1.37, P=0.30) or corrosion (P=0.20) were identified. Higher numbers of treatment cycles showed higher amounts of corrosion (mean: 1cycle = 0.06%, 25cycles = 0.52% and 50cycles = 1.45%). In contrast, higher numbers of treatment cycles showed lower amounts of protein residue (P