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The detection of both viable and viable but non-culturable (VBNC) <i>Escherichia coli</i> O157:H7 is a crucial part of food safety. Traditional culture-dependent methods are lengthy, expensive, laborious, and unable to detect VBNC. Hence, there is a need to develop a rapid, simple, and cost-effective detection method to differentiate between viable/dead <i>E. coli</i> O157:H7 and detect VBNC cells. In this work, recombinase polymerase amplification (RPA) was developed for the detection of viable <i>E. coli</i> O157:H7 through integration with propidium monoazide (PMAxx). Initially, two primer sets, targeting two different genes (<i>rfbE</i> and <i>stx</i>) were selected, and DNA amplification by RPA combined with PMAxx treatment and the lateral flow assay (LFA) was carried out. Subsequently, the <i>rfbE</i> gene target was found to be more effective in inhibiting the amplification from dead cells and detecting only viable <i>E. coli</i> O157:H7. The assay’s detection limit was found to be 10² CFU/mL for VBNC <i>E. coli</i> O157:H7 when applied to spiked commercial beverages including milk, apple juice, and drinking water. pH values from 3 to 11 showed no significant effect on the efficacy of the assay. The PMAxx-RPA-LFA was completed at 39 °C within 40 min. This study introduces a rapid, robust, reliable, and reproducible method for detecting viable bacterial counts. In conclusion, the optimised assay has the potential to be used by the food and beverage industry in quality assurance related to <i>E. coli</i> O157:H7.