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item Marmer, William
item Dudley, Robert

Submitted to: Journal of American Leather Chemists Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/15/2004
Publication Date: 5/1/2005
Citation: Marmer, W.N., Dudley, R.L. 2005. Rapid oxidative dehairing using alkaline hydrogen peroxide and potassium cyanate: reuse of the dehairing reagents. Journal of American Leather Chemists Association. 100(5):165-173.

Interpretive Summary: One of the major sources of bacterial contamination of meat is the animal's hide. During flaying in the slaughterhouse, there is the potential of cross-contamination from the hide to the carcass. Removal of the hair from the carcass before flaying greatly reduces the pathogen contamination on the carcass. Such a procedure could be implemented, provided that the integrity of the hide is maintained for subsequent conversion to leather. We have developed a new rapid dehairing procedure for use in the slaughterhouse and this paper discusses the reuse (recycling) of the dehairing agents to economically dehair more than one animal. The dehairing solution consisted of hydrogen peroxide, potassium cyanate, and sodium hydroxide. We followed the disappearance of the active ingredients during the course of a number of dehairing cycles, and determined that the solution could be recycled 7 to 8 times, thus reducing the cost of dehairing. The results show that scale-up trials are merited; eventual adoption of the procedure will provide the meat packing and leather industries and the consumer with a safe and environmentally sound process to control pathogens and prepare hides for conversion into leather.

Technical Abstract: Studies have continued on rapid dehairing of cattlehide using an oxidative system of alkaline hydrogen peroxide and potassium cyanate. For economic viability, the dehairing mixture needs to be used for more than one dehairing cycle. The number of cycles is dependent upon the residual concentration of the reagents in solution, namely, NaOH, H2O2 and KOCN. The concentrations of these reagents were measured after each dehairing cycle. In addition the solubilized protein concentration and the amount of insoluble material suspended in solution were determined. NaOH, H2O2 and KOCN all decreased with an increase in the number of dehairing cycles. After the 7th or 8th cycle the dehairing times had increased to the point where dehairing still occurred, but was no longer rapid. There was a buildup of soluble protein in solution as well as suspended (insoluble) material with increasing dehairing cycles. Both the protein and insoluble (mostly hair) material reacted with the dehairing chemicals, resulting in a decrease in the efficacy of the dehairing mixture. Nevertheless, the system appears to offer a viable alternative to sulfide-based rapid dehairing, and further experimentation on a pilot plant scale is merited.