Bacteriocins: Natural Antimicrobials as Effective Food Preservatives
Michael L. Chikindas
Department of Food Science
Cook College, Rutgers University, NJ
Lactic acid bacteria (LAB) are the microorganisms which have for centuries been associated with foods, either as spoilage or fermenting/processing organisms. Virtually all bacteria produce small proteins, called bacteriocins, which mainly kill closely related organisms and help the host survive and establish an ecological niche. Bacteriocin-producing LAB are naturally present in many foods, including salad (Franz et al 1998), cheese (Ennahar et al 1996), dry and fermented sausages (Enan et al 1996, Palacios et al 1999), etc.
Most bacteriocins kill sensitive cells due to the dissipation of the proton motive force, ATP depletion and leakage of small ions and molecules from the cell (Montville and Bruno 1994). Although bacteriocins are highly active antimicrobials, they are not antibiotics.
Currently, nisin is the only LAB bacteriocin that is commercially used as a food preservative for decades in over than 50 countries. However, many bacteriocins from LAB are active against foodborne pathogens and food spoilage microorganisms, and stable over a wide range of environmental conditions. Therefore, in the future these molecules should be considered as food preservatives, especially when used as a part of hurdle technology.