Naturally Occurring Substances Exhibit Antimicrobial Activity in Food

April 22, 1998

Naturally Occurring Substances Exhibit Antimicrobial Activity in Food

Food Safety and Preservation

According to the Council for Agricultural Science and Technology (CAST), an international consortium of 36 scientific and professional societies, many biologically derived substances exhibit antimicrobial properties in the foods in which they normally are found or may be developed for commercial use as additives to other foods requiring preservation.

Food preservation is becoming ever more critical to the survival and well-being of humans. The importance of food safety to our society is evidenced by major actions taken by federal, state, and local health and regulatory authorities in recent years. These include the new regulations for meat, poultry, and seafood inspection, as well as the President’s 1997 National Food Safety Initiative. Among the approaches employed in achieving food preservation by inhibiting growth of undesirable microorganisms, is the use of chemical agents exhibiting antimicrobial activity. These chemicals may be either synthetic compounds intentionally added to foods or naturally occurring, biologically derived substances.

"Consumer perception that use of industrially synthesized food antimicrobials may be associated with potential toxicological problems has generated interest in the food industry for the use of naturally occurring compounds," states Dr. John N. Sofos, Professor of Animal Sciences at Colorado State University and chair of the recently released CAST task force report Naturally Occurring Antimicrobials in Food. "Commonly used synthetic antimicrobials also are found naturally in many food products, and their toxicological safety as food additives is ensured by regulatory authorities." However, interest in so-called natural foods has generated interest in, and incentive for, development and use of naturally occurring antimicrobials in foods.

What Are Naturally Occurring Antimicrobials?

Numerous naturally occurring antimicrobial agents are present in animal and plant tissues, where they probably evolved as part of their hosts’ defense mechanisms against invasion by microorganisms. Natural antimicrobials can be derived from barks, stems, leaves, flowers and fruits of plants, various animal tissues, or from microorganisms. Noted sources of natural antimicrobials are herbs, spices, fruits, milk, eggs, and lactic acid bacteria used in food fermentation.

Future of Naturally Occurring Antimicrobials

Naturally occurring antimicrobials could be useful as individual factors or hurdles in multifactor food preservation systems. This CAST report discusses the chemistry, occurrence, activities, mechanisms of action, uses, application potential, and research and development needs of naturally occurring antimicrobials.

"Of the many natural antimicrobials discussed in this report," Sofos says, "only a few have been tested or applied to foods." Examples of antimicrobials of natural origin that have been approved and have found certain uses include egg-white lysozyme, hydrogen peroxide, ethanol, the antibiotic natamycin, and the bacteriocin nisin.

For more extensive use of natural antimicrobials, there is a need for research to examine their 

  •  efficacy and functionality in models of food systems and foods,
  • toxicology and safety in food formulations,
  • interactions with food components and other preservative systems,
  • mechanisms of action against microorganisms,
  • influences on food quality (e.g., nutritional and sensory),
  • methods for application in commercial formulations, and
  • extraction, isolation, and economical production.

 Naturally occurring antimicrobials are abundant in the environment. The desire for expanded use is obvious, especially in light of consumer demands for minimally processed, safe foods of adequate shelf life and convenience, and the global need for increasing the supply of food. With availability of economical food preservation systems based on natural antimicrobials, the world will have an additional weapon in the struggle against hunger.

Naturally Occurring Antimicrobials in Food, 103 pages, is available for $28.00 from CAST.