Evaluation of 3M Molecular Detection Assay (MDA) and 3M Petrifilm Salmonella Express (SALX) System for Detection of Salmonella in Naturally Contaminated Poultry and Their Processing Environment

Introduction: In Malaysia, poultry are slaughtered and retail in wet markets under very poor hygienic conditions. Poultry is also considered to be a major source of Salmonella in many countries. High prevalence of Salmonella in poultry poses an imminent risk to public health. To prevent the occurrence of this pathogen in poultry, effective and efficient Salmonella control programs must be adopted throughout the poultry production chain. Rapid or alternative methods are important, as they reduce the detection time for Salmonella considerably in comparison to culture-based methods.

Purpose: This research evaluated the efficacy of 3M Molecular Detection Assay (MDA) and the 3M Petrifilm Salmonella Express (SALX) System against culture-based method for the detection of Salmonella in naturally contaminated poultry and their environment.

Methods: A total of 145 naturally contaminated samples (whole chickens, chicken cuts, environmental swabs and water samples) were obtained from different wet markets in Penang and Kedah, Malaysia. The samples were analyzed for the presence for Salmonella using 3M MDA, 3M SALX System and ISO 6579:2002 conventional culture-based method.

Results: Detection of Salmonella by both rapid methods was comparable with the conventional ISO method. Highest number of positive samples were detected with conventional method (133/145), followed by 3M MDA (125/145) and 3M Petrifilm SALX System (123/145). The sensitivity, specificity, negative predictive value, positive predictive value and accuracy were 92.23, 91.67, 55.0, 99.2 and 93.1%, respectively for the 3M MDA and 92.48, 100, 55.0, 100 and 93.10%, respectively for 3M Petrifilm SALX System. As both the 3M MDA and 3M Petrifilm SALX System yielded similar kappa results, it indicates substantial agreement with the culture-based method.  

Significance: The data from this study therefore support the use of the 3M Petrifilm SALX System and the 3M MDA as rapid and reliable screening methods for Salmonella detection in poultry and its processing environment.