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Chapter 34 : Biopreservation of Foods
Category: Applied and Industrial Microbiology; Food Microbiology
This chapter provides an overview of the biologically based preservation technologies termed “biopreservation.” Acid production by lactic acid bacteria (LAB) in temperature-abused foods (controlled acidification) is covered in the chapter. Some LAB produce antimicrobial proteins, called bacteriocins, which inhibit spoilage and pathogenic bacteria without changing (e.g., through acidification, protein denaturation, and other processes) the physicochemical nature of the food. While organic acids are usually added to foods, LAB can produce lactic acid in situ. The controlled production of acid in situ is an important form of biopreservation. There are many different ways to use bacteriocins in foods. The first is to add bacteriocins directly to the food for the purpose of inhibiting spoilage or pathogenic bacteria. The second way to use bacteriocins is to add bacteriocinogenic cultures to the food or use them as starter cultures that produce the bacteriocin in situ. A third way to use bacteriocins is to facilitate the use of defined starter cultures in fermented foods. Emulsifiers such as Tween 80 or the entrapment of the pediocin in multilamellar vesicles increases pediocin effectiveness in fatty foods. Nisin is the only bacteriocin approved internationally for use in foods. The biological methods of food preservation covered here mark only the beginning of the biopreservation era in the food industry.
A generic bacteriocin operon. The structural gene (struct) codes for a prepropeptide which is modified and excreted by the processing gene products (P1 and P2) and may be regulated by a signal transduction pathway coded for by reg 1 and reg 2. For additional abbreviations and explanations, see the text.
Models for pore formation and detergent-like mechanisms of bacteriocin action.
Parallel mechanisms of antibiotic and bacteriocin resistance a
Analogies between the use of insecticides in production agriculture and the use of antimicrobials for food safety