Detection of Salmonella spp. in Eight Complex Food Matrices Using Polymerase Chain Reaction Assay

Conventional methods for the detection of Salmonella based on culturing are time-consuming and laborious. The aim of this study was to develop a template preparation method and polymerase chain reaction (PCR) assay for the detection of Salmonella spp. in egg yolk, pizza, ground beef, pork, pork sausage, chicken drumsticks, mayonnaise and Minas cheese. The DNA extraction was performed with thermal lysis followed by nucleic acid purification with phenol-chloroform. After the use of this template preparation method, no inhibitory substances for the PCR were observed in those eight complex food matrices. The PCR technique detected Salmonella spp. with a sensitivity of 1 cfu/mL (colony forming unit per milliliter) of all food matrices tested after 18h of enrichment in buffered peptone water. This method is relatively inexpensive, reduces time of analysis in comparison to the reference method, and can be used in food microbiological analyses and epidemiological studies. Practical ApplicationsThe developed template preparation method and PCR are an efficient means to detect Salmonella spp. in eight complex food matrices (in egg yolk, pizza, ground beef, pork, pork sausage, chicken drumsticks, mayonnaise and Minas cheese) after a 18h of enrichment. This represents a great advantage in order to reduce cost and time of analysis by shorter time of incubation and reduction in enrichment steps in comparison to the analytical reference method. This method can be used in food microbiological analyses and epidemiological studies.