Detection results from dilution series of Salmonella DNA containing multiple target loci‡.

‡The results are presented as a minus sign for responses of ≤0 counts over threshold, a plus sign for responses of >0 but ≤500 counts over threshold, two plus signs for responses of >500 but ≤1,500 counts over threshold, and three plus signs for responses of >1,500 counts over threshold. The threshold for each MCT ion was calculated from 8 NTC samples. Responses are calculated from the average of five replicates.*All 28 MCTs assigned to the fourteen primer/probe signatures were included and monitored in the assay, but for clarity only responses from positive targets are shown. The other 9 markers for all dilutions were called negative after analyzing the responses from both MCTs of each marker. The left MCT ion of the target pair monitors incorporated F primer; the right MCT ion monitors incorporated probe.∧Copy number for each Salmonella-specific target loci. BLAST analysis indicated that gene targets were single copy per genome. The dilution of stock DNA to obtain the starting concentration (3×105) for making the 6 log dilutions was calculated based on a genome size of 4.8 megabases.