A comparative study of sampling techniques for monitoring carcass contamination

Four bacteriological sampling techniques i.e. the excision, double swab, agar contract and modified agar contact techniques were compared by sampling pig carcasses before and after chilling. As well as assessing the advantages and disadvantages of the techniques particular attention was paid to variation due to the effects of chilling. The agar contact technique cannot be used for determining the contamination of carcasses because too many plates became overcrowded with micro-organisms. Results obtained by the double swab and modified agar technique gave standard deviations which were significantly higher than those of the excision technique. This may indicate a superior repeatability of the excision technique. Statistical analysis of the results showed that chilling influenced the differences between sampling techniques. The excision technique is to be regarded as the most suitable in view of its high accuracy and precision. When the technique is used properly, carcass damage is only small or negligible.