Food microbiology

ikbm

The group works mainly with lactic acid bacteria (lactococci) and propionibacteria. Understanding the life and death of these microorganisms will help understand and control the complex processes of fermented products.

Professor Thor Langsrud Foto: M. Sanderud

Stability of the fermentation, the impact of the important “good” bacteria on other organisms, stress effects, metabolism of probiotics, expression of flavour compounds and protein degradation are key issues for this group.

The group has a long tradition and strong competence in fermentation processes, particularly within the dairy segment. One example is the composition of starter cultures and the proteolytic and autolytic activity of different species and strains. (Autolysis is the destruction of a cell after its death by the action of its own enzymes, which break down its structural molecules.) A recent doctor thesis on this topic is: "Autolysis of Lactococcus og Propionibacterium in mixed cultures." (Norwegian).

Given the importance of the starter culture to the character of the final product, understandign the metobolism of the different bacteria is of vital importance. The group has done extensive research particularly on propionibacteria; at present one doctor student is looking at pigment and hemolysin activity of these bacteria. Other active research is on antibacterial compounds from propionibacteria.

Probiotics means the use of microorganisms in a positive way to benefit health. The production of bacteriocins – antimicrobial peptides - is one type of defense against unwanted growth of bacteria in foods. New isolates are being characterized both from a food production and a health benefit perspective. The group works closely with other internal and external groups on this topic. One doctor student is looking into bioactive peptides from fish.

The understanding of the bacterial stress responses in food environments is another important issue for the group. Food and agriculture systems expose bacteria to heat, cold, salt, acid, oxidative, and other stresses that provoke bacterial responses designed to cope with the particular stress situation. Bacteria possess mechanisms to adapt to stress situation, changing their properties and the capacity to withstand other types of stresses.

The group is actively using a new pathogen lab now available at IKBM. This will enhance the research on pathogens combined with probiotic bacteria. Bacillus cereus and Listeria species, both able to make problems in the dairy industry,are the main pathogens in this groups research.

The group Food Microbiology (2007):

Thor Langsrud, Professor Ph.D.
Terje Sørhaug, Professor Ph.D.
Christin Vanberg, Ph.D. student, (2003-2007)
Therese Faye, associated researcher
Margreet J. Brovold, engineer
Associated member, Gerd Vegarud, Professor, Food Proteins group.

Publications last 5 years.

Collaborations.
Professor Ingolf Nes on genetic aspects.
Industrial relations with Tine through “Matalliansen”
Matforsk
The Norwegian School of Veterinary Science
NTNU (organic chemistry)
International partners are e.g. INRA (France), University of Limerick and University College of Cork (Ireland).

Events.
Members of this group together with other groups will arrange the 5th International Symposium on Propionibacteria and Bifidobacteria in 2007. The last meeting was held in 2004 in Saint-Malo, France.


Oppdatert: 20.05.05
Utskriftsvennlig versjon : Arkiv : Tips en venn