Abstract

River authorities are becoming increasingly concerned with the level of dissolved solids such as salt in trade effluent. Although at the present time no restrictions have been imposed, limitations on dissolved solids may be set in the near future. Consequently there is a need to look for alternative methods of holding hides in a good state of preservation over the limited period of time that is required to collect sufficient hides of the required class and weight range and transport them to the tannery. Biocides can be applied to hides either as a spray to the hide surface or as a soak liquor for complete immersion of the hide. The work described in this paper shows that a 5% solution of sodium chlorite or a mixture of Gloquat C (15%) and Glokill 77 (10%) sprayed over the flesh surface of a hide will retard bacterial attack for a period of six days at 26°C. Hides immersed in a mixture of Vantocil lB (0.4%) and Vantoc CL (0.2%) remained in a good state of preservation for eight days at 26°C. The cost of these treatments was in the region of 3-4 pence per hide. Rapid chilling and storage of hides at -1.0°C, i.e., just above the freezing point of hide tissue, held the hides in a satisfactory state of preservation for three weeks. The hide, freshly flayed was cooled to 3°C in 22 min when air at -10°C was blown over the exposed flesh surface at a speed of 100 m/min. Increasing the air speed had relatively little effect on the rate of chilling. Chilling with air at -9.5°C speeded the rate of chilling, but with the disadvantage that thinner regions of the hide froze before the thicker regions had reached 3°C. To avoid damage to the hides it is preferable to chill with air at -1.0°C. To be able to collect and distribute fresh hides so avoiding the use of curing salt, storage at chill temperature would appear to be the more practical proposition to treatment with a biocide.