Chemical preservatives and natural food antimicrobials

Food antimicrobials are chemical preservatives added to or present in foods that retard growth of or kill microbes, but they do not include therapeutic antibiotic-type compounds used for growth promotion or disease treatment in food animals. These compounds are divided into the traditional and the naturally occurring. Antimicrobials are classified as traditional when they (i) have been used for many years, (ii) are approved by many countries and/or regulatory bodies for inclusion in foods as antimicrobial agents, or (iii) are produced by synthetic processes as opposed to being natural extracts (e.g., industrial fermentation of nisin from Lactococcus lactis subsp. lactis). Ironically, many synthetic and traditional food antimicrobials are found in nature; examples include acetic acid from vinegar and lactoperoxidase in fluid milk. The use of natural antimicrobials will likely continue to grow in popularity. Additional research is needed to determine the levels of natural antimicrobials required for successful inhibition of foodborne pathogens, their mechanisms of action, and their safety. The development of novel applications of existing antimicrobials, including encapsulation, incorporation into edible polymers and the use of combinations of antimicrobials capable of synergistic inhibition of foodborne microorganisms, is being investigated. Major challenges in future applications include demonstrating the efficacy of antimicrobial compounds in food products at concentrations that do not have adverse sensory effects, as well as controlling the cost of these interventions.