Tag: Listeria

Reports

24-hour detection of undesirable microbes in food / 24-hour detection of undesirable microbes in food

Published:

01/12/2009

Authors:

Eyjólfur Reynisson, Sveinn Haukur Magnússon, Árni Rafn Rúnarsson, Viggó Þór Marteinsson

Supported by:

Tækniþróunarsjóður, AVS

Contact

Viggó Marteinsson

Research Group Leader

viggo@matis.is

24-hour detection of undesirable microbes in food / 24-hour detection of undesirable microbes in food

The aim of the project was to develop and establish methods for rapid detection of undesirable bacteria in agricultural and marine products as well as other foods. With traditional methods as used today, results are obtained after 3 and up to 7 days, but with the methods developed in this project, it is possible to get results in a few hours or within 24 hours. The method is based on real-time PCR methodology and specific amplification of the genetic material of pathogenic bacteria and other undesirable bacteria. Diagnostic methods have been developed for major pathogens (Salmonella, Campylobacter, Listeria monocytogenes, Vibrio parahaemolyticus) in milk, meat and fish products as well as for specific spoilage bacteria in food. The results of the project will improve services to the food industry in Iceland by detecting unwanted microorganisms much earlier so that it is possible to intervene in production processes and thereby increase consumer safety in agricultural and fish products.

The aim of this project was to develop and set up new methods for rapid identification of undesirable bacteria in food and feed. With today's conventional and accredited culture methods results can be expected after 3 and up to 7 days. With the new methods to be taken in use and was developed in this project, the time of diagnostic procedure will decrease to few hours or to one working day. The detection methods are based on real ‐ time PCR technology and a specific amplification of genetic material of the undesired bacteria. Diagnostic methods for the most common pathogens (Salmonella, Campylobacter, Listeria monocytogenes, Vibrio parahaemolyticus) in meat‐, milk and fish products were developed through as well as quantitative assays for the main spoilage bacteria in fish. The results of the project will be used to improve the service for the Icelandic food industry on the domestic‐ and overseas markets by having rapid diagnostic methods for bacterial contamination at hand.

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Reports

Effect of high pressure processing in reducing Listeria spp. and on the textural and microstructural properties of cold smoked salmon (CSS)

Published:

01/08/2007

Authors:

Hannes Hafsteinsson, Ásbjörn Jónsson, Valur Norðri Gunnlaugsson, Birna Guðbjörnsdóttir, Magnús Guðmundsson

Supported by:

Icelandic Research Center Research Fund

Contact

Valur Norðri Gunnlaugsson

Research Group Leader

valur.n.gunnlaugsson@matis.is

Effect of high pressure processing in reducing Listeria spp. and on the textural and microstructural properties of cold smoked salmon (CSS)

The main objective of the project was to investigate the effect of hypertension (400-900 MPa) on the death of the bacterium Listeria monocytogenes and quality factors (image structure, texture and color) in cold smoked salmon after treatment for 10, 20, 30 and 60 seconds. Effects on the total number of aerobic bacteria, lactic acid bacteria and Bacillus spores were also studied. Two experiments were performed, one in July 2005 and the other in November 2006. The study showed that short-term hypertension treatment was effective in improving the quality and safety of cold-smoked products. Due to changes in the appearance and texture of the products, further research is needed. This new method promises to meet the requirements for longer shelf life of smoked salmon. The study is of great value to the industry, due to the innovation of using high pressure for a short time (seconds) to eliminate the bacterium Listeria in smoked salmon and thus increase the shelf life of this valuable product.

The main object of this research was to study the effects of high pressure processing (400-900 MPa) on the survival of Listeria monocytogenes and the characteristics (microstructure, texture and color) of cold smoked salmon when it was processed for 10, 20, 30 and 60 seconds. The changes in counts of total aerobic bacteria, lactic acid bacteria and Bacillus spores were also studied. Two experiments were carried out, one in July 2005 and the second in November 2006. It is concluded here that the combination of high pressure and short time treatment is very effective to improve the quality and safety of cold smoked products. However, because of the changes in the visual appearance and texture, further studies are necessary. This new development is promising to meet requirements for extended shelf life of ready-to-eat cold smoked salmon with high microbiological quality and safety. This study is of high industrial relevance because it combines the innovative approach of using high pressure processing for short time (seconds) to reduce the number of Listeria in cold smoked salmon and thereby extend the shelf life of this valuable product.

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