Novel touchdown-PCR method for the detection of putrescine producing Gram-negative bacteria in food products

► Seven pairs of PCR primers were designed to investigate putrescine metabolism. ► New touchdown PCR method was developed and tested with 32 Gram-negative bacteria. ► Agmatine and putrescine productions were confirmed by HPLC in all strains tested. ► Biogenic amine contents corresponded to the incidence of genes investigated. ► Sequences analyses confirmed the accuracy of new primers and the new method.