The immunogenic lipo-oligosaccharides (LOS) of the cell wall from seven Finnish field strains and three ATCC strains of Brachyspira hyodysenteriae were compared by SDS-PAGE. The LOS profiles were heterogeneous between the strains. Hyperimmune sera for five B. hyodysenteriae strains were used to determine the diagnostic specificity of microagglutination, immunodiffusion and microscopic agglutination tests. The hyperimmune sera cross-reacted with the other species of genus Bracyspira using each of these methods. The microagglutination test became strain-specifi c for B. hyodysenteriae when the antigen was boiled. The boiling of the antigen led to lowered titres. Serum samples from three and colostrum samples from one herd with a chronic B. hyodysenteriae infection were used to evaluate the diagnostic sensitivity of the microagglutination test in detecting the infection; its sensitivity was fairly low.
The use of fresh produce all year round has increased enourmously. Availability problems, due to seasonal change because of Finland’s geo-graphical position, have been solved by increasing import from distant countries. New methods, which enable an effective reduction of the growth of spoilage microbes, have also made it possible to import fresh produce from all over the world. On the other hand, the worldwide import and longer storage periods have increased the risk of occurence of pathogenic bacteria in fresh produce.