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Category: Food Microbiology
Biological Control of Food-Challenging Microorganisms, Page 1 of 2
< Previous page | Next page > /docserver/preview/fulltext/10.1128/9781555819972/9781555819965.ch28-1.gif /docserver/preview/fulltext/10.1128/9781555819972/9781555819965.ch28-2.gifAbstract:
This chapter provides an overview of current and emerging methods of food preservation using live microorganisms and biologically derived substances. This field of study is rapidly evolving, as interest in so-called “natural” and “organic” products has grown exponentially among the public in the past 25 years. Biological methods of preservation are of particular interest, again, due to their natural/biological origins and safety compared with commonly used chemical preservatives and physical treatments. Broadly speaking, biological preservatives can be divided into several distinct groups: (i) live microorganisms, (ii) plant derivatives, (iii) proteinaceous compounds of both eukaryotic and prokaryotic origins, and (iv) bacteriophages. Each group presents its own set of pros and cons, which must be carefully considered and balanced for every individual food application. The safety of biopreservatives is paramount and is the final basis on which a treatment may be chosen for application in the food industry, regardless of the efficacy demonstrated in laboratory studies. Impact on the quality of food is also a concern, as any loss of quality will result in an undesirable product. Quality concerns can be addressed through various techniques aimed at decreasing the amount of preservatives needed while increasing efficacy. These include novel modes of delivery, as well as synergistically acting combination treatments, both of which show promise.
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Environmental factors essential for biopreservation by bacteriocinogenic GRAS microorganisms. Image from reference 14 .
Natural antimicrobials of interest for food preservation.
Chemical structure of polylysine.
Generic bacteriocin operon. The operon's structural gene bacA codes for a prebacteriocin (numbered 1). The bacteriocin processing and transport are carried out with assistance of the products of bacC, coding for the accessory protein (3), and bacD, coding for the ABC transporter (4). The bacteriocin producer cell's immunity to its own product is ensured by the bacB gene product, the immunity protein (2). The bacteriocin translocation machinery is engaged in the energy-dependent process, resulting in the cleavage of the bacteriocin's leader region (1b) and release of the mature bacteriocin (1a). The immunity protein (2) protects the bacteriocin recognition site (6) by preventing the bacteriocin (1a) from interacting with this site. The bacE gene codes for the histidine protein kinase (5), which is activated by the mature bacteriocin molecule working as a pheromone. The phosphorylated response regulator (7P) interacts with the bacteriocin operon's promoter region, triggering transcription.
Examples of commercially available bacteriocin-producing food-grade microorganisms a
Proteinaceous food biopreservatives examples
Bacteriocins: AMPs with varying charges, structures, and targets
Bacteriocins are not antibiotics a
Bacteriocins’ activity in food products (recent publications)
Increased activity of bacteriocins when combined with synergistically acting stressors a
Bacteriophages as an aid in infectious diseases and food safety: commonalities and differences in food and infection scenarios