Partial Characterization of Nine Bacteriocins Produced by Lactic Acid Bacteria Isolated from Cold-Smoked Salmon with Activity againstListeria monocytogenes

Abstract

Nine LAB bacteriocin-producers, isolated from vacuum-packaged cold-smoked salmon (CSS), were phenotypically and genotypically identified as Lactobacillus curvatus, Lactobacillus delbrueckii, Lactobacillus fermentum, Enterococcus faecium, and Pediococcus acidilactici. Their bacteriocins were partially characterized. The antimicrobial spectrum was determined against Listeria monocytogenes, E. faecalis, E. faecium, and Staphylococcus aureus. The molecular size of bacteriocins ranged from 2.8 to 4.5 kDa. They were inactivated by treatment with proteolytic enzymes but not by lipolytic or glycolytic enzymes. Maximal activity against L. monocytogenes ranged between 800 and 10000 AU/mL at pH 6.5. Most of the bacteriocins maintained full activity in a pH range of 2.0 to 8.0 but were partially or completely inactivated at pH 10.0. After heating at 60°C and 100°C, only two bacteriocins from Lb. curvatus strains partially lost activity. All bacteriocins showed a narrow spectrum of activity and a high anti-listerial activity, which is characteristic of the class IIa bacteriocins. Isolated bacteriocinproducing LAB could be used successfully in the bio-preservation of CSS and development of new potential bio-preservatives for CSS active against L. monocytogenes.

Purification and Mode of Action of Antilisterial Bacteriocins Produced byLactobacillus pentosus SJ65 Isolated fromUttapamBatter

“…Thus, the bacteriocin preparation was stable at acidic and neutral pH but unstable at alkaline pH, which was also observed in an earlier report (Tome et al . ). The bacteriocin retained its activity up to 100C, but complete loss of activity was observed at 121C indicating it was heat stable and not autoclavable (Table ).…”

Potential beneficial properties of bacteriocin-producing lactic acid bacteria isolated from smoked salmon

“…The activity of the cell‐free supernatants of the studied strains against most of the tested L. monocytogenes strains (Table 1) is quite interesting, particularly because many reports have shown that L. monocytogenes is an important foodborne pathogen, present in several foods, including fresh trout samples and smoked salmon (Hangard‐Vidaud et al. 1989; Tomé et al. 2008, 2009).…”

“…acidilactici ET34 and Ent. faecium ET05, ET12 and ET88 were isolated from smoked salmon (Tomé et al. 2009) obtained from same production plant.…”

“…acidilactici ET34 and Ent. faecium ET05, ET12 and ET88 were isolated from smoked salmon (Tomé et al 2009) obtained from same production plant. These strains, Lactobacillus sakei ATCC 15521, Enterococcus faecalis ATCC 19443 and other LAB used in the bacteriocin spectrum of activity were cultured in MRS broth (Difco).…”

Recent Advances in Minimal Heat Processing of Fish: Effects on Microbiological Activity and Safety

“…They should grow during temperature abuse, either producing acid or bacteriocins, or make the product inedible, which would warn the consumer of a hazard (Juneja 2006). This approach has been investigated for cold-smoked salmon by using lactic acid bacteria (LAB) (Tome et al 2008(Tome et al , 2009). Among heat-processed products, little information is available for the addition of LAB on seafood, but pork has been investigated (Laursen et al 2009).…”