For some strains of bacteria, we sell complete viability PCR kits, which include strain-specific primer sets that have been validated at Biotium, as well as in publications in most cases. However any validated primer sets may be used to target your species of interest. We and others have found that amplicon length can affect your viability PCR results. Using longer amplicons generally results in better suppression of dead cell PCR products. For an example see this publication: Banihashimi A., et al. (2012) Long-amplicon propidium monoazide-PCR enumeration assay to detect viable Campylobacter and Salmonella. J. Appl. Miobiol. dio 10.1111/j.1365-2672.2012.05382.x.
While you can perform viability PCR with amplicons as short at 100 bp, we advise that you use longer amplicons for better results.