Development of a rapid diagnostic kit for detection of Salmonella Enteritidis in food using indirect coagglutination technique

Abstract

The objective of this study was to develop a rapid, simple, cheap, sensitive, and specific assay for detection of Salmonella Enteritidis in food. The kitprototype was developed by using indirect coagglutination technique with three main components, namely Staphylococcus aureus Cowan I, rabbit IgG anti-chicken Fc IgY and chicken IgY anti-S. Enteritidis. Isa Brown layer chickens were used to produce specific antibodies against S. Enteritidis. Monospecific antisera were prepared by absorption method. Staphylococcus aureus Cowan I was coupled with rabbit IgG anti-chicken Fc IgY and monospecific antisera anti-S. Enteritidis. Kit-prototype was compared with multiplex polymerase chain reaction to determine sensitivity and specificity of kit-prototype. Artificially inoculated food sample was used to determine the limit of detection of kit-prototype in a food sample. Indirect coagglutination kit-prototype was able to differentiate positive control from negative control without self-agglutination reaction. This assay has a high specificity to S. Enteritidis without significant cross-reactivity towards other bacteria. Kit-prototype was able to detect 108 CFU/mL of S. Enteritidis in the buffer and 1 CFU/mL of S. Enteritidis in a food sample after selective enrichment procedure. The application of this kit was able to give a fast result (reaction can be observed in 10 sec), to be applied in a sample without extraction in the preparation of antigen and to reduce detection time of S. Enteritidis in food until 4 days.