Evaluation of sampling methods to assess the microbiological status of cattle hides

Abstract

The study focused on the performance of selected sampling methods for recovery of: (a) marker organism (nalidixic acid resistant E. coli K12) topically inoculated onto hide of experimental cattle (to achieve > 6 log 10 CFU/ cm 2 ), and (b) naturally occurring microflora from hide of experimental cattle. Recoveries of bacteria by each of five consecutive passes using wet sponge swabbing of the hide was determined, and compared with bacteria remaining on the hair (recovered by taking hair-clippings). These results showed that: (i) the highest recovery (5.52 log 10 CFU/ cm 2) of the topically inoculated marker organism was achieved by the first pass of the wet sponge swabbing technique, (ii) significant levels of the marker organism (5.15 log 10 CFU/ cm 2) remained on the hair even after five consecutive swabbing passes, and (iii) the highest recovery of natural flora (from non-inoculated hide) was achieved by the hair-clipping sampling technique. Recoveries of both the marker organism (topically inoculated on hide) and the natural flora (non-inoculated hide) by each of the three hide sampling techniques used (single-pass wet swab, wet–dry swab, and electric hair-clipping) were determined. The results showed that: (i) the efficacy of the hide sampling techniques in recovery of topically inoculated marker organism was in the order: wet–dry swabbing > single-pass wet swabbing > hair-clipping, and (ii) the efficacy of the sampling techniques in recovery of natural flora from non-inoculated hide was, in the order of the highest to lowest efficiency; hair-clipping > wet–dry swabbing > single-pass wet swabbing. From a practical perspective of the microbiological monitoring of hide under commercial abattoir conditions, swabbing techniques are more acceptable than clipping techniques. However, further research is necessary to optimise and validate microbiological sampling techniques for animal coats.