Abstract

Though chilling has been adopted as a short term preservation method for hides and skins in many western countries, no systematic attempt has been made to study the microbiological aspects related to the method. Hence, an attempt has been made in the present investigation to study the cold activity of the major skin-borne bacteria at different temperatures and their collagenolytic activity. Among the 5 bacterial isolates studied in this investigation, Macrococcus caseolyticus was found to be the most cold tolerant bacterium exhibiting growth even at 2°C. Another bacterium, Bacillus sphaericus exhibited tolerance at 4°C. These two bacteria need to be controlled while designing a chilling method for the preservation of hides and skins. The inference from the collagenolytic activity study is that there is no relationship between collagenolytic activity at 37°C and the cold activity: as Bacillus firmus which exhibited the maximum activity at that temperature was found to be most cold-sensitive bacterium. The other important inference from the study is that it is necessary to use a biocide in combination with chilling at 4°C if the storage duration has to be extended beyond 9 days. The two biocides investigated in the study were found to inhibit the growth of all 5 bacterial isolates for 3 weeks and the minimum inhibitory concentrations for both were determined.