Discovery of novel biopreservation agents with inhibitory effects on growth of food-borne pathogens and their application to seafood products

Institut National des Sciences et Technologies de la Mer (INSTM), Rue 2 Mars 1934, 2025 Salammbô, Tunis, Tunisia.
Research in Microbiology (Impact Factor: 2.71). 01/2012; 163(1):44-54. DOI: 10.1016/j.resmic.2011.08.005
Source: PubMed


Selection of protective cultures is relevant in order to biopreserve and improve the functional safety of food products, mainly through inhibition of spoilage and/or pathogenic bacteria. Accordingly, the present study investigated potential applications of lactic acid bacteria (LAB) in the biopreservation of fish and shellfish products. For this purpose, a collection of 84 LAB strains isolated from sea bass (Dicentrarchus labrax) and sea bream (Sparus aurata) was identified and characterized for their inhibitory activities against the most relevant seafood-spoilage and pathogenic bacteria potentially present in commercial products. The bioactive strains belonged to the genus Enterococcus and exhibited inhibition against Carnobacterium sp, Bacillus sp, Listeria monocytogenes, Aeromonas salmonicida, Aeromonas hydrophila and Vibrio anguillarum. Treatment of cell-free extracts of the LAB strains with proteases revealed the proteinaceous nature of the inhibition. Interestingly, the cell-free extracts containing bacteriocins remained 100% active after treatment up to 100 °C for 30 min or 121 °C for 15 min. Molecular analysis led to identification of the bacteriocins investigated, including enterocins A, B, L50 and P. All of these proteins demonstrated remarkable anti-Listeria activity and were found to be heat-resistant small class IIa bacteriocins. The results presented in this work open the way for potential applications of these LAB strains to the biopreservation of minimally-processed seafood products.

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Available from: Monia El Bour, Feb 23, 2014
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    • "(Dicentrarchus labrax) and sea bream (Sparus aurata) showed higher heat resistance since they kept the activity after treatment at 100ºC for 30 min and at 121ºC for 15 min.[48]Bacteriocin DU10 was found to be active at pH 2, 4, 6, 8, 10 and 12. "
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    ABSTRACT: A novel bacteriocin produced by avian duck isolated lactic acid bacterium (LAB), Enterococcus faecalis DU10 was isolated. This bacteriocin showed broad spectrum of antibacterial activity against important food borne pathogens and purified by size exclusion chromatography followed by RP-HPLC C-18 column. Tricine-SDS PAGE revealed the presence of a band with an estimated molecular mass of 6.3 kDa. The zymogram clearly linked the antimicrobial activity with this band. This result was further confirmed by MALDI-TOF MS, since a sharp peak corresponding to 6.313 kDa was detected and the functional groups were revealed by FTIR. Bacteriocin DU10 activity was found sensitive to proteinase-K and pepsin and partially affected by trypsin and α -chymotrypsin. The activity of bacteriocin DU10 was partially resistant to heat treatments ranging from 30 to 90°C for 30 min. It also withstood a treatment at 121°C for 10 min. Cytotoxicity of bacteriocin DU10 by MTT assay showed the viability of HT-29 and HeLa cells decreased a 60 ± 0.7% and 43 ± 4.8%, respectively, in the presence of 3,200 AU/mL of bacteriocin. The strain withstood 0.3% w/v of bile oxgall and pH 2 affects the bacterial growth between 2 and 4 h of incubation. Adhesion properties examined with HT-29 cell line showed 69.85% initial population of strain E. faecalis DU10 was found to be strongly adhered to this cell line. These results conclude bacteriocin DU10 may be used as a potential biopreservative and E. faecalis DU10 may be employed as a potential probiont to control Salmonella infections.
    Full-text · Article · Jan 2016 · Preparative Biochemistry & Biotechnology
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    • "This is why many industrials are moving toward the use of protective microbial cultures, mainly LAB, able to produce antagonistic metabolites such as bacteriocins, peptides and/or low-weight non-proteinaceous compounds (organic acids, fatty acids, H 2 O 2 , etc.). Many scientific evidences or proof-of-concept in literature underline the great potential of such an approach to combat pathogenic or spoilage microorganisms in various food products such as meat (Budde et al., 2003; Vermeiren et al., 2004; Castellano et al., 2008), fish (Brillet et al., 2005; Tomé et al., 2008; Chahad et al., 2012), bakery products (Dal Bello et al., 2007; Gerez et al., 2009; Ryan et al., 2011) and vegetables (Trias et al., 2008; Randazzo et al., 2009). However, in contrast to probiotics (Gregoret et al., 2013), only a limited number of commercial protective cultures are marketed today, and this statement is especially true for antifungal bioprotective cultures in dairy products. "
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    Full-text · Article · Feb 2015 · Food Microbiology
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    • "Bacteriocin-producing enterococci are widespread in nature. They have been isolated from numerous sources, such as dairy products (Foulqui e Moreno et al. 2006), fermented sausages (Cocolin et al. 2007), fish (Bourouni Chahad et al. 2012), vegetables (Bennik et al. 1998; Zendo et al. 2005) and mammalian gastrointestinal tract (Carina Audisio et al. 2000; Brand~ ao et al. 2010). "
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