Very few studies have demonstrated the effect of propionic acid on the total microbial flora According To Golden et al. (1995) concentration of 0.9% propionic acid was able to
reduce the CFU of Listeria monocytogenes by 4 log in brain heart infusion broth at pH 3.5 at 28 1C in 65 days as compared to the acidified control that took 172 days