A Natural Way of Food Preservation: Bacteriocins and applications
Since the consumers demand foods produced without additives, new friendly preservation strategies become significant in processing of foods. Bacteriocins are ribosomally synthesized peptides produced from many bacterial strains which are approved as natural due to being degraded by digestive enzymes. In Lactic acid bacteria (LAB), many strains have been identified as bacteriocin producers. In fact, nisin was approved by Food and Drug Administration (FDA) to be used as food additive in some foods. Lacticin and pediocin producers, Lactococcus lactis and Pediococcus acidilactici, respectively, have been used as protective cultures in food system. Bacteriocins produced by some LAB have shown wide antimicrobial activity against food related pathogens species such as Bacillus, Listeria, Staphylococcus and Clostridium. However, in recent years bacteriocins having specifically narrow-spectrum antimicrobial activity have been introduced. Bacteriocins are used either directly in food systems or by the addition of producer strains. In this way, it has been possible to prevent pathogenic microorganisms in various fermented food products. However, the effectiveness of the LAB bacteriocins may reduce due to their adsorption on to the hydrophobic surfaces and degradation with proteases. Therefore, the combinational usage of bacteriocins with other preservation methods, such as high hydrostatic pressure, pulse electrical field or essential oils, were reported successful at inhibiting pathogens including the Gram negatives. In the first part of the chapter, the general introduction to bacteriocins and new generation bacteriocins are discussed. In the second part, the applications of bacteriocins in different food systems have been explained and the combinational usage of bacteriocins together with different preservation methods have been exemplified.