Methods of enhancing or improving the shelf life and/or the quality of an edible product using lactic acid bacterial organisms which are defective in their pyruvate metabolism are provided. The lactic acid bacterial organisms may be defective with respect to pyruvate formate lyase (Pfl) and/or lactate dehydrogenase (Ldh) activity. The organisms may overexpress a gene coding for an NAD+ regenerating enzyme such as NADH oxidase encoded by nox gene.
