Rapid identification of Salmonella in dairy products by P-CEIA

Abstract

Background and Aim: Salmonella contamination is a major problem in poultry and food industry. Lack of on-time diagnosis of the bacteria may cause irreparable economic loss. Speed, repeatability and cost-benefits are the most important parameters. Faster, easier and more economic monitoring of pathogens (e.g. Salmonella.) is essential in the whole process. Routine bacterial culture methods and Antibody-Enzyme Immunoassay (ELISA) are time consuming and costly. The aim of this study was to compare Polymixin Coated Polyester Cloth (P-CEIA) with culture and ELISA in identification and rapid diagnosis of different Salmonella serovars in dairy products. Materials and Methods: In order to compare Ab-EIA and P-CEIA, different dilutions of S. typhimorium Ra-30 were prepared in peptone water (BPW, pH=7.4). From the 20 samples of milk and cream, 10 suspicious slamonella contaminated samples had been surveyed by the two methods. Results: The sensitivity of P-CEIA method was 106 cfu/ml while the sensitivity of ab-EIA was estimated to be 105 cfu/ml. The sensitivities of the two methods were equal following heat treatment in the presence of sodium deoxy-cholate. Ab-EIA detected 5 and 3 suspicious samples of milk and cream, respectively. PCEIA detected 3 and 6 of the contaminated samples. The first method required 14 hours less time than the other method.Conclusion: Our data shows that P-CEIA is a rapid, economic and sustainable method for Salmonella detection in dairy products.

Keywords

• Salmonella
• P-CEIA
• Polymixin-B
• Dairy Products
• ELISA