Projects / Programmes
DETECTION OF SOURCES AND SPREADING OF L. MONOCYTOGENES IN HOLDINGS AND FOOD PRODUCTION PLANTS FOR FOOD SAFETY ASSURANCE
| Code |
Science |
Field |
Subfield |
| 4.04.05 |
Biotechnical sciences |
Veterinarian medicine |
Sanitary protection of animal origin food |
| Code |
Science |
Field |
| B007 |
Biomedical sciences |
Medicine (human and vertebrates) |
| Code |
Science |
Field |
| 4.03 |
Agricultural and Veterinary Sciences |
Veterinary science |
L. monocytogenes, zoonosis, food safety, molecular typing, surveillance
Researchers (19)
Organisations (2)
Abstract
Listeria spp. are ubiquitous microorganisms widespread in nature. Their main reservoirs are soil, plants, feed and water, but also infected domestic and wild animals and humans. The only species pathogenic for humans is L. monocytogenes which causes listeriosis. Healthy adults are rarely affected while certain populations, e.g. newborns, small children, aged people and immunocompromised persons, are more prone to disease. L. monocytogenes has the highest morbidity and mortality rates among all bacteria causing food-borne infections. In addition, it is the most resistant to extreme environmental conditions among all non-sporogenous bacteria. Due to its resistance to low temperatures it can multiply at all stages of cold chain and therefore represents a high risk for contamination of surfaces and food.
The highest risk for human health is represented by ready to eat food. Food containing less than 100 cfu/g of L. monocytogens is not considered as a major risk for healthy adult population. However, inadequate treatment of food may lead to increased numbers of L. monocytogenes. Contaminated food has to be withdrawn from retail which causes huge economic losses.
In Slovenia, only food samples have been analysed so far within the scope of monitoring of zoonoses, while monitoring of the disease in animals is not performed. There are also no data available on sources and modes of transmission of L. monocytogenes in different environments of food production industry. To determine the source of infection, isolates obtained from different environments (animals, food production industry, food, humans) will have to be typed and compared. Classical serotyping lacks sensitivity and will therefore be supplemented with modern methods including molecular serotyping (PCR) and genotyping (PFGE). This approach will enable us to follow the spreading of bacterium at all stages of food production chain, from farm to fork.
Within the scope of the proposed project, the most common entry points of L. monocytogenes into the food production chain will be investigated. The study will be performed at different levels and the sampling will include natural environment, animals, food production industrial plants, food and humans. Typing of the collected isolates will represent the basis for revealing the most frequent epizootiological links.
L. monocytogenes infections in animals will be monitored and analysed and routes of transmission from the primary animal production to the industrial plants will be investigated. Systematic sampling will take place in the food production industrial plants in order to determine critical points for internal and external contamination. We expect to identify the major sources and routes of transmission of L. monocytogenes in industrial plants for production of red meat, poultry meat, milk and fish products and ready to eat food. The most frequently contaminated food will be additionally investigated. All isolates will be serotyped using classical and molecular methods. Epidemiological analysis, which will include human isolates, will be performed on the basis of PFGE genotyping.
The work on the proposed project will include professionals from different fields. This will contribute to knowledge transmission and use of harmonised modern methods (PCR, PFGE) which will represent the basis for preparation of preventive measures regarding L. monocytogenes contamination of food.
The results of the proposed project will represent an important contribution to the production of healthy and safe food and to improvement of public health. Determination of critical points and preparation of preventive measures against spreading of L. monocytogenes at different stages of primary animal production and food production will enable us to limit food contamination and prevent the economic losses due to trade ban.
Significance for science
In the scope of the project, many new information and scientific knowledge on the incidence, number and characteristics of L. monocytogenes isolates, originating form humans, animals, food, animal feed, natural environment, environment of the food processing plants and from different segments of the food chain, were gained. Researchers from all the participating groups were involved, and were additionally educated and trained. The results of the research were forwarded to the project partners, clients from whom the samples or isolates of L. monocytogenes were obtained, broader professional community and to the relevant administrative departments. The data were transmitted in the form of seminars, permanent trainings, professional consultations and publications in Slovene or international scientific literature. The project has created a large archive collection of listeriae (assumed to be the largest in Slovenia and probably beyond), for which great interest is shown by the other research institutions, including the National Institute of Chemistry in Ljubljana where different factors of pathogenicity (hemolysins, listeriolysin) are studied. A preliminary testing of 20 archival isolates of L. monocytogenes was performed in the context of the work by a young researcher Sara Primec (mentor G. Anderluh), but further research will depend on the success of obtaining adequate financing. Physicians, veterinary practitioners, pathologists and epidemiologists of the medical and veterinary profession are showing interest for the results of our research to help them evaluate the conditions, where greater risk for the infection with L. monocytogenes is expected. In addition, they are very interested in the use of diagnostic methods which allow reliable results in the shortest possible time. Improvements or modifications of various diagnostic methods will also be useful for the researchers from other laboratories. The procedure for the isolation of L. monocytogenes from the water was adapted, which will enable the investigation also of the samples with lower concentration of listeriae. In addition, the procedure for the isolation of listeriae from the air will be particularly suitable for the investigation of contamination in the areas of the food processing industry. In the process of classical serotyping, the procedure for the determination of flagellar antigens was very simplified. It is shorter, cheaper and more reliable in comparison to the standard procedure; therefore it enables more efficient work in the research and routine laboratories. In addition, the improvement of PFGE method leads toward the simplification of the procedure for determination the ApaI pulsotypes. Members of the project group are also the founding members of the Centre of Excellence NAMASTE, within which the effect of nano materials on the survival of listeriae in the natural environment and in the environment of the food processing plants is studied. Through this center, headquartered at the Institute Jozef Stefan, a very good cooperation with many partners from various sectors of the industry is achieved.
Significance for the country
New knowledge and the use of modern diagnostic methods, which were introduced in the scope of the project work, have proven to be indispensable, especially in the cases of larger interconnected infections (outbreaks) with L. monocytogenes in animals and humans. On the basis of PFGE typing, the support was given when identifying the sources of infection and the measures for preventing the emergence of new infections were suggested. For this, the harmonization of methodology in medical and veterinary laboratories was extremely important as being necessary for the typing of isolates in the epidemiological studies. The results are extremely important for the corporations of agricultural and food processing profession as the infection of animals or contamination of foods with listeriae cause a very large economic and health damage. Diagnostic laboratories (mainly of the regional units of NVI) are showing interest for forwarding the protocols of validated procedures for the isolation, identification and typing of L. monocytogenes. Based on the assessment of the situation regarding the frequency of occurrence of L. monocytogenes in the selected samples, we participated in the preparation of improvements of the technologies aiming for the greater food safety. The results of the project are suggesting the guidelines how to decrease the contamination of the foods of animal origin with listeriae and how to raise awareness or knowledge of the consumers toward the safer preparation of food, which will impact the protection of health and the improvement of healthcare. Since L. monocytogenes was isolated also from numerous samples of the wild animals (roe deer, red deer, foxes), hunters are very interested in our results. In a common action, the testing of game in the spring time was already performed, and a similar action is planned for the autumn months. The main interest is for the evaluation of risk to infect game with the remains of animal feed on the farms. It is also necessary to investigate whether it is possible that the colonized game can contaminate the agricultural land and thus, indirectly, also the domestic animals and crops.
Most important scientific results
Annual report
2011,
2012,
2013,
final report
Most important socioeconomically and culturally relevant results
Annual report
2011,
2012,
2013,
final report
