Rapid methods have been developed to detect bacterial contamination in food. It is now possible to determine in just a few hours whether the food contains undesirable microorganisms, but this greatly increases food safety and the waiting time for the results of microbiological analyzes is reduced from 2-6 days to less than 24 hours.
The AVS project, which aims to develop rapid methods for detecting common pathogens in food and specific spoilage bacteria in fish, has been completed. The analysis time with these methods is from 2 up to 6 days shorter than the reference methods and the fastest ones take about 4 hours.
One-day certification of food safety - within 24 hours of sending samples for analysis - is very important for companies in the food industry, especially with regard to food pathogens, and will become even more important in the near future. Rapid PCR analysis enables food producers to intervene immediately, control the processing of the raw material or stop distribution if the product is found to contain undesirable micro-organisms or does not meet quality requirements. Technology therefore contributes to improved quality and the image of food, which is a very important factor in maintaining Iceland's good image for healthy agricultural and marine products.
The project developed several methods for different bacteria. Development of high-speed Salmonella analyzes in different products were performed and showed comparable analytical skills and an accredited NMKL method, e.g. the comparable sensitivity of the methods to analysis was demonstrated Salmonella in chicken pox. The real-time PCR method analyzed Salmonella furthermore with high reliability in all other raw materials tested, i.e. fishmeal, roe, shrimp, salmon and haddock.
Diagnostic tests Campylobacter of the method in chicken feces and chickens have similarly shown that the bacterium can be detected in samples containing only 10-100 bacteria per gram with full reliability after pre-breeding overnight. Comparison with accredited NMKL cultures further showed that the real time PCR method had a sensitivity comparable to or greater than the accredited NMKL method. Other methods for detecting pathogenic bacteria were also set up Listeria monocytogens and Vibrio parahaemolyticus with good results. Further information can be found in the project report.
Fortunately, foods rarely contain pathogenic micro-organisms, but there are a host of other harmless bacterial species that promote tissue breakdown and grow steadily during storage. During decomposition, various compounds are formed, which are usually accompanied by odor and the quality of the products is reduced accordingly. In all cases, storage methods are therefore about controlling the growth of these micro-organisms. Research on these bacteria in fish has shown which bacterial species are most at work there, and with knowledge of their amount in the fish during production or storage, the quality of the products can be assessed and even their shelf life can be predicted.
In this project, a rapid test was developed to measure the level of harmful bacteria separately. This test can be used to predict shelf life, to assess the condition of raw materials and products or for internal quality control in fish processing plants. The bacterial species that are most commonly targeted are spears in this context Pseudomonas types and Photobacterium phosphoreum but their damaging activity in fish has been demonstrated under different storage conditions.
The knowledge and experience gained in the project has also made it possible to set up new methods for other bacterial species at a lower cost than before, and further activities in this field are planned.
Interested parties can get further information from the project manager, Eyjólfur Reynisson, eyjolfur.reynisson@matis.is, at Matís ohf.
Project report: 24-hour analysis of undesirable micro-organisms in food.