The effects of treating bovine hide with steam at subatmospheric pressure on bacterial numbers and leather quality.

Aims: To examine the effect of subatmospheric steam treatment on total viable counts (TVCs) on bovine hide and on the quality of derived leather.

Methods And Results: Pieces of bovine hide were heated to 75 degrees C (+/-2 degrees C) (n = 3) or 80 degrees C (+/-2 degrees C) (n = 3) for periods of 1, 10 or 20 s by the application of steam at subatmospheric pressure in a laboratory scale apparatus. Treated hide pieces and untreated controls were tanned and the quality of leather was assessed. Treatment at 80 degrees C (T80) reduced the TVC on hide pieces by 2.95 (1 s), 3.33 (10 s) and 3.99 (20 s) log10 CFU cm-2 (P > 0.05). Treatment at 75 degrees C (T75) reduced the TVC on hide pieces by 1.87 (1 s), 2.51 (10 s) and 2.56 (20 s) log10 CFU cm-2 (P > 0.05). The grain on all treated hides was damaged resulting in sueding on derived leather. Sueding was observed on 100% of surfaces from T80-treated samples and on 18 (1 s) to 84% (20 s) of the surfaces of T75 samples.

Conclusions: The magnitude of TVC reductions achieved using T75 and T80 could limit the impact and scale of contamination transfer to the carcass during dehiding. However, because of the sueding observed on derived leather, it is unlikely that either T75 or T80 would be a commercially valid operation during routine slaughter operations.

Significance And Impact Of The Study: Hide decontamination would provide an important critical control point for beef processing, however there are currently no commercially available treatments.