The wide range of extremely effective naturally occurring antimicrobial systems include those derived from animals (e.g., enzymes such as lysozyme and lactoperoxidase; other proteins such as lactoferrin, lactoferricin, ovotransferrin, and serum transferrins; small peptides such as histatins and magainins; and the immune system), those derived from plants (e.g., phytoalexins, low-molecular-weight components of herbs and spices; phenolics such as oleuropein; and essential oils) and those derived from microorganisms (e.g., bacteriocins such as nisin and pediocin). An increasing number of such natural systems is being deliberately utilized for food preservation, or being explored for such use. The future potential is substantial, particularly as the efficacy of these systems is demonstrated in additive or synergistic combinations with some of the other antimicrobial factors that we can employ to improve the safety and shelf stability of foods. While ''naturalness'' alone is not necessarily a sufficient objective for these developments, the use of natural inhibitors as components of systems that can together enhance the effectiveness of preservation, with advantages in product quality and safety, justifies pursuit.
