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The purpose of this Brief is to provide a global view of the concept of biopreservation and its potential and existing applications in the different food sectors. Biopreservation, an approach already experimented with by our ancestors, has been used empirically for centuries and now the rationale behind it is becoming increasingly popular, applied singly or in combination with novel and classical food processing technologies. The growing world population, together with the globalization of the food market and consumer demand for foods that are ready to eat, lightly preserved, fresh-tasting, and rich in flavor, nutrients, and bioactive compounds, is forcing the food industry to develop less aggressive food preservation methods.

Inhaltsverzeichnis

Frontmatter

Chapter 1. Introduction

Abstract
Microbal foodborne diseases are a constant concern to human health, as shown by annual statistics published by official institutions (http://​www.​cdc.​gov/​foodborneburden/​; http://​www.​efsa.​europa.​eu/​en/​efsajournal/​pub/​3129.​htm). The globalization of the food market and the large-scale distribution and processing of raw materials and food products create new ecological niches to which microorganisms from different regions of the world may adapt, raising new problems that the food industry must solve. This trend increases as the food chain tends to be more complex in several ways, including transportation distance, processing steps, distribution of raw materials, and shelf life extension of the finished products. The increase of the more susceptible populations (e.g., the young, elderly, and immunocompromised individuals), the migration of populations from rural to urban areas, the overexploitation of natural resources (such as soil and water) and the climatic changes, are also factors to be taken into consideration. The food industry also has to satisfy the newer consumer habits. In the past years, there has been a growing demand of consumers for foods that are fresh-tasting, lightly preserved, ready-to-eat, and (possibly) with health-promoting effects. Consumer organizations are also more and more concerned about the quality of foods and the ways in which they are produced.
Antonio Gálvez, Rosario Lucas López, Rubén Pérez Pulido, María José Grande Burgos

Chapter 2. Natural Antimicrobials for Food Biopreservation

Abstract
Biopreservation or biocontrol refers to the use of natural or controlled microbiota, or its antibacterial products to extend the shelf life and enhance the safety of foods (Stiles 1996). Since lactic acid bacteria (LAB) occur naturally in many food systems and have a long history of safe use in fermented foods, thus classed as Generally Regarded As Safe (GRAS), they have a great potential for extended use in biopreservation. Antimicrobial substances from other natural sources, such as antimicrobial proteins or peptides from animal secretions, or bioactive molecules from plant or animal defense systems have also been exploited in different ways for food biopreservation.
Antonio Gálvez, Rosario Lucas López, Rubén Pérez Pulido, María José Grande Burgos

Chapter 3. Application of Lactic Acid Bacteria and Their Bacteriocins for Food Biopreservation

Abstract
Microbes and/or their natural products have played key roles in the preservation of foods during mankind history (Ross et al. 2002). The rational exploitation of microbial antagonism based on scientific knowledge has been possible after the discovery of the biochemical nature of the antimicrobial substances produced by microorganisms. Bacteriocins produced by the lactic acid bacteria (LAB) have several features that still make them attractive for food preservation: (1) LAB have a long history of safe use in foods; (2) LAB and their cell products—including bacteriocins—are generally recognised as safe; (3) LAB bacteriocins are not active and non-toxic on eukaryotic cells, and (4) due to their proteinaceous nature, bacteriocins are expected to become inactivated by digestive proteases and not exert significant effects on gut microbiota at the concentrations ingested with the food. In addition, LAB bacteriocins may be suitable as preservatives, given (1) their sometimes broad antimicrobial spectrum, including food poisoning and spoilage bacteria, (2) their synergistic activity with other antimicrobials, (3) a bactericidal mode of action exerted at membrane level, which avoids cross resistance with antibiotics of clinical use, (4) stability under the heat and pH conditions achieved under processing of many foods, and (5) their genetic determinants are usually plasmid-encoded, which facilitates genetic manipulation and development of producer strains with improved technological properties. Bacteriocin-encoding plasmids may be transferred to other strains by natural processes, but at the same time there is a risk for loss of the plasmid together with the bacteriocin production capacity.
Antonio Gálvez, Rosario Lucas López, Rubén Pérez Pulido, María José Grande Burgos

Chapter 4. Biopreservation of Meats and Meat Products

Abstract
The microbial populations most frequently associated with the meat environment are known to primarily belong to the groups Enterobacteriaceae, lactic acid bacteria (LAB), Brochothrix thermosphacta, and pseudomonads (Borch et al. 1996; Labadie 1999; Nychas et al. 2008). Microbial metabolism of meat during growth results in microbial spoilage, with the development of offodors which make the product undesirable for human consumption (Jackson et al. 1997). Also, pathogenic bacteria initially present at low concentrations may grow during meat spoilage may proliferate during refrigeration storage, especially Listeria monocytogenes.
Antonio Gálvez, Rosario Lucas López, Rubén Pérez Pulido, María José Grande Burgos

Chapter 5. Biopreservation of Milk and Dairy Products

Abstract
Milk may act as vehicle for human pathogenic bacteria (reviewed by Claeys et al. 2013). Pasteurization of milk before human consumption or for the manufacture of dairy products is often required or recommended. Pasteurizarion will decrease the background spoilage microbiota, but it will not yield a sterile product. Some traditional, highly appreciated fermented dairy foods are still made from raw milk, and there is an ongoing debate on the benefits of consuming raw milk versus pasteurized milk (Claeys et al. 2013). According to foodborne disease reports from different industrialized countries, milk and milk products are implicated in 1–5 % of the total bacterial foodborne outbreaks, with 39.1 % attributed to milk, 53.1 % to cheese and 7.8 % to other milk products (De Buyser et al. 2001; Claeys et al. 2013). Bacteriocins seem an attractive approach to improve the safety of milk and dairy products (especially in those made from raw milk), and at the same time may offer some potential technological applications such as in acceleration of cheese ripening (Table 5.1). The antimicrobial effects of bacteriocins and/or their produced strains have been investigated both in raw milks and in several types of dairy products.
Antonio Gálvez, Rosario Lucas López, Rubén Pérez Pulido, María José Grande Burgos

Chapter 6. Biopreservation of Egg Products

Abstract
A few studies have investigated the preservation of egg and egg products by application of bacteriocins (Table 6.1). The commercial use of liquid whole egg requires processing in order to prolong its shelf-life and to inactivate foodborne pathogens. As an alternative to conventional pasteurization, an ultrapasteurization processes (i.e., heating at >60 °C for <3.5 min) was developed, which, when coupled with aseptic processing and packaging, produced liquid whole egg with a shelf life of at least 10 weeks at 4 °C. The use of effective aseptic filling and packaging systems (to prevent postpasteurization contamination) remains an essential component in the production of ultrapasteurized liquid whole egg with an extended pathogen-free shelf life. Contrary to Salmonella, conventional minimal egg pasteurization processes do not grant a complete inactivation of L. monocytogenes. As a matter of fact, Listeria species can be isolated from commercially broken raw liquid whole egg. Therefore, it was proposed to use bacteriocins for the control of Listeria in this food system (Schuman and Sheldon 2003). Addition of nisin to pasteurized liquid whole egg reduced the viable counts of L. monocytogenes, increased the product refrigerated shelf-life, and protected the liquid egg from growth of L. monocytogenes and B. cereus during storage (Delves-Broughton et al. 1992; Knight et al. 1999; Schuman and Sheldon 2003). Nisin (200 IU/ml) extended the shelf life of conventionally pasteurized liquid whole egg at 6 °C by 9 to 11 days relative to nisin-free control samples (Delves-Broughton et al. 1992). The addition of nisin (1,000 IU/ml) to pH-adjusted ultrapasteurized liquid whole egg reduced L. monocytogenes populations by 1.6 to over 3.3 log CFU/ml and delayed (pH 7.5) or prevented (pH 6.6) the growth of the pathogen for 8–12 weeks at 4 and 10 °C (Schuman and Sheldon 2003). Both nisin and pediocin PA-1/Ach acted synergistically with heat treatments against L. monocytogenes (Knight et al. 1999; Muriana 1996). Nisin added at 10 mg/l significantly decreased the decimal reduction times (D-values) for L. monocytogenes in liquid whole egg. This effect was greater when the bacteriocin was added at least 2 h before application of heat treatments (Knight et al. 1999). In spite of the fact that nisin is not active on Gram-negative bacteria, nisin addition also increased the heat sensitivity of Salmonella enteritidis PT4 in liquid whole egg and in egg white during pasteurization (Boziaris et al. 1998).
Antonio Gálvez, Rosario Lucas López, Rubén Pérez Pulido, María José Grande Burgos

Chapter 7. Biopreservation of Seafoods

Abstract
Listeria monocytogenes is the main bacterial pathogen of concern in seafood products. One study found L. monocytogenes in ca. 30 % of smoked-fish samples, although viable counts were below 100 CFU/g (Uyttendaele et al. 2009). Another study found populations of L. monocytogenes greater than 102 CFU/g in 2.6 % of fresh fish, 5.1 % in smoked fish and 10 % in salted-fish purchased in fish farms, while 20 % of smoked fish purchased in a fish market were also contaminated (Basti et al. 2006). The bacterium was also found in raw fillets of catfish (23.5 %), trout (5.7 %), tilapia (10.3 %), and salmon (10.6 %) (Pao et al. 2008), or in 44.5 % of raw freshwater fish tested (Yücel and Balci 2010). Bacteriocin preparations have been tested singly or in combination with other hurdles to control L. monocytogenes in different types of seafoods (Table 7.1).
Antonio Gálvez, Rosario Lucas López, Rubén Pérez Pulido, María José Grande Burgos

Chapter 8. Biopreservation of Vegetable Foods

Abstract
Fresh produce products can become contaminated with human pathogenic bacteria from different sources (such as manure, irrigation water, insects, and during harvesting and other process operations), and have been implicated in a number of outbreaks (Lynch et al. 2009). Several bacteriocin preparations (such as nisin, pediocin, or enterocin AS-48) have been assayed for inactivation of foodborne pathogenic or toxinogenic bacteria (such as Listeria monocytogenes, Bacillus cereus, and Bacillus weihenstephanensis, Escherichia coli, Salmonella and other enterobacteria) on the surfaces of fresh-cut vegetables and on sprouted seeds (Galvez et al. 2008; Randazzo et al. 2009a, b; Abriouel et al. 2010) (Table 8.1). Bacteriocin treatments have also been proposed for decontamination of whole fruit surfaces, and to avoid transmission of pathogenic bacteria from fruit surfaces to processed fruits (Ukuku et al. 2005; Silveira et al. 2008), and to decrease bacterial survival of bacteria on sliced fruit surfaces during storage.
Antonio Gálvez, Rosario Lucas López, Rubén Pérez Pulido, María José Grande Burgos

Chapter 9. Regulations

Abstract
Application of bioprotection strategies in food preservation may be restricted by laws from different countries that may differ considerably in their fundamentals end practical effects. Some of them are related directly to addition of bioprotectants to foods, but others not less important may be related to apparently secondary aspects such as labelling, packaging, export, use of biological agents or genetically modified organisms.
Antonio Gálvez, Rosario Lucas López, Rubén Pérez Pulido, María José Grande Burgos
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