An improved method is provided for inactivating microorganisms in food products by introducing an edible phenolic compound in a food product and subjecting the resulting food product containing phenolic compound to high pressure conditions. This particular combination of physical and chemical treatments on the food products inactivates undesirable microorganisms in a food product to a significantly greater degree possible than achieved with any one of the treatments by itself, and the combined antimicrobial effect of these different types of treatments is synergistically greater than any additive effect that might be expected from the individual treatments.