Development of a Rapid Detection Method of Salmonella Spp. on Chicken Skin by Real-Time Polymerase Chain Reaction

Abstract

Salmonella is a major contributor to food-borne illness with contaminated poultry meat being recognized as a chief source of the infection. The handling of raw poultry has been reported as one of the most frequent causes of Salmonella ingestion and human sickness. The use of magnetic particles (beads) coated with a highly specific antibody have become common and serve as a valuable tool in the detection of Salmonella and other food borne pathogens in complex food matrices. With the speed, cultural precision and sensitivity of this method, it is extremely likely that it will replace or modify the tiresome traditional protocol in the recognition of Salmonella serovars. This method has the capacity of concentrating low levels of the bacteria while simultaneously removing them from the food sample. With so many contaminants and numerous other bacteria being present, this allows for specific enrichment of the target microbe for greater detection potential. Real-time Polymerase Chain Reaction allows confirmation of the target bacteria presences on the chicken skin and has been used extensively as an alternative method of detection. If the contaminants and food components such as fat remain, the sensitivity and accuracy of real-time PCR is severely decreased. Magnetite (Fe3O4) and silica-magnetite composites were produced within the lab and conjugated with anti-Salmonella antibody for its isolation from raw chicken skin. Real-time PCR was used for positive identification. These magnetic beads have shown great potential to meet the demand for rapid and efficient detection techniques in food safety. Preliminary test show an 80% detection rate when inoculating Salmonella at a level of 13 cells per 16 square inch, with potential of detection at even lower levels in a twelve hour period. Success would mean a significant reduction in recalls, since the product should still be present in the plant. With the preparation of magnetic composites being carried out as a bench top procedure, commercial bead use is not needed, thus tremendously reducing cost.