Effects of processing on detection and quantification of the parvalbumin gene in Atlantic salmon (Salmo salar)

Consumption of Atlantic salmon is a common cause of fish allergies with parvalbumin (Sal s1) being the major allergen. The presence of DNA encoding Sal s1 indicates the presence of Atlantic salmon in food. Using real-time polymerase chain reaction (PCR), the effects of food processing on the ability to detect and quantify the Sal s1 gene were determined. The method was specific for salmon and did not cross-react with 53 other species. Baking and pressure cooking caused a 5–100-fold decrease in detectable copies of the Sal s1 gene. Despite a 98% reduction in detectable copies following pressure cooking for 60 min, the relative standard deviation (RSD) between replicates was 20% and the response was 100-fold grater than the lowest copy number of Sal s1 reliably detected by the assay. Despite efforts to develop a quantitative assay, the PCR assay was qualitative. It is impossible to predict the effects of food matrices not included in this study, some of which may affect the reliability of the assay. Analyses of raw and pressure cooked salmon using a commercial PCR kit indicated comparable results to the PCR assay.