Bioburden of postmortem bone tissues with a procurement time exceeding 36 h

To qualify for bone donation many criteria must be met. For procurement, two time intervals-a postmortem interval (PMI) of 6 h (hours) until cooling of the deceased and a maximum procurement time of tissues within 24/36 h postmortem are mandatory. Expanding the procurement to donors with a longer PMI would be helpful e.g. to have more time to contact relatives for consent for donation. A loss of biomechanical quality of bone tissues should not be expected in the PMI until procurement, but the question of microbiological contamination remains. Therefore, samples from the iliac crest were procured under standard procurement conditions between 48 and 54 h (n = 14, group 1) and 72-78 h (n = 7, group 2) postmortem (pm). Samples were immediately frozen after procurement at < - 18 °C and sent to the German Institute for Tissue and Cell Replacement (DIZG) for mechanical preparation. Additionally, chloroform treatment was performed at the tissue bank of the Charité Berlin. After each step the samples were refrozen and sent to a contracted microbiological lab for bioburden testing according to the European Pharmacopoeia. Samples were tested after procurement, preparation, and chloroform treatment respectively. As acceptance criterion a maximum amount of 9 × 10⁴ colony forming units per gram (CFU/g) tissue was defined. All samples were within the defined limit with a maximum value of 2.5 × 10² CFU/g. These values are in the range of bone tissues procured under non-strict-aseptic procurement conditions within 24 or 36 h and are within the capacity of the peracetic acid sterilization process used by several tissue banks.