title: Effective survival of immobilized Lactobacillus casei during ripening and heat treatment of probiotic dry-fermented sausages and investigation of the microbial dynamics.
abstract: The aim was the assessment of immobilized Lactobacillus casei ATCC 393 on wheat in the production of probiotic dry-fermented sausages and the investigation of the microbial dynamics. For comparison, sausages containing either free L. casei ATCC 393 or no starter culture were also prepared. During ripening, the numbers of lactobacilli exceeded 7 log cfu/g, while a drastic decrease was observed in enterobacteria, staphylococci and pseudomonas counts. Microbial diversity was further studied applying a PCR-DGGE protocol. Members of Lactobacillus, Leuconostoc, Lactococcus, Carnobacterium, Brochothrix, Bacillus and Debaryomyces were the main microbial populations detected. Microbiological and strain-specific multiplex PCR analysis confirmed that the levels of L. casei ATCC 393 in the samples after 66 days of ripening were above the minimum concentration for conferring a probiotic effect (≥ 6 log cfu/g). However, after heat treatment, this strain was detected at the above levels, only in sausages containing immobilized cells.
authors.affiliation: Food Biotechnology Group, Section of Analytical Environmental and Applied Chemistry, Department of Chemistry, University of Patras, GR-26500 Patras, Greece.; Applied Microbiology and Molecular Biotechnology Research Group, Department of Molecular Biology & Genetics, Democritus University of Thrace, Alexandroupolis 68100, Greece.
authors.forename: Marianthi
authors.initials: M
authors.lastname: Sidira
authors.forename: Athanasios
authors.initials: A
authors.lastname: Karapetsas
authors.forename: Alex
authors.initials: A
authors.lastname: Galanis
authors.forename: Maria
authors.initials: M
authors.lastname: Kanellaki
authors.forename: Yiannis
authors.initials: Y
authors.lastname: Kourkoutas
mesh_terms: D018914:Cells, Immobilized; D055598:Chemical Phenomena; D015169:Colony Count, Microbial; D004755:Enterobacteriaceae / Q000302:isolation & purification; D005285:Fermentation; D005506:Food Contamination / Q000517:prevention & control; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology; D006358:Hot Temperature; D006801:Humans; D007778:Lactobacillus / Q000302:isolation & purification*; D008461:Meat Products / Q000032:analysis / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D019936:Probiotics / Q000378:metabolism*; D011549:Pseudomonas / Q000302:isolation & purification; D013210:Staphylococcus / Q000302:isolation & purification; D013649:Taste
keywords: Dry-fermented sausages; L. casei ATCC 393; Multiplex PCR; PCR-DGGE; Probiotics