Tuula Johansson

Learn More
AIMS The aim of this study was to evaluate the efficiency of four isolation methods for the detection of pathogenic Yersinia enterocolitica from pig intestinal content. METHODS AND RESULTS The four methods comprised of 15 isolation steps using selective enrichments (irgasan-ticarcillin-potassium chlorate and modified Rappaport broth) and mildly selective(More)
One hundred and ten samples of ready-to-eat, vacuum-packed, smoked and cold-salted fish products were collected from retail outlets in southern Finland during 1996 for examination of the occurrence and level of Listeria monocytogenes. The samples originated from 12 producers. Positive samples with levels exceeding 100 CFU/g were encountered mainly in one of(More)
Poultry production is under strict official control in Finland. Fifteen years after the introduction of 'competitive exclusion' treatment the majority of growers (over 70%) use it routinely. The number of Salmonella-positive flocks is less than 5% and the incidence of Salmonella-contaminated broiler carcasses has been 5-11% in the last two years. The(More)
In February 1999, an outbreak of listeriosis caused by Listeria monocytogenes serotype 3a occurred in Finland. All isolates were identical. The outbreak strain was first isolated in 1997 in dairy butter. This dairy began delivery to a tertiary care hospital (TCH) in June 1998. From June 1998 to April 1999, 25 case patients were identified (20 with sepsis, 4(More)
One hundred and six Yersinia enterocolitica serogroup O:3, biotype 4 isolated from human and porcine samples in 1984 and in the years 1993 5 were examined by pulsed-field gel electrophoresis (PFGE). The genomic profiles produced by the enzymes NotI and XbaI were studied. Sixteen (A-P) and 8 (1-8) different pulsotypes were obtained, respectively. By(More)
  • T Johansson
  • 1998
Listeria monocytogenes blood agar (LMBA) was compared to Listeria selective agar based on lithium chloride and ceftazidime (LA) and to the Oxford and Palcam media recommended by ISO and IDF for the detection and enumeration of L. monocytogenes from foodstuffs and food-processing environments. LMBA is based on trypticase soy agar with the following(More)
Salmonella enterica serotype Bovismorbificans is a rare serotype in Finland. In June 2009, a nationwide outbreak of S. Bovismorbificans infections occurred, and 42 clinical isolates were identified. We conducted a case-control study enrolling 28 cases and 48 matched controls, and found ready-to-eat alfalfa sprouts associated with the infection (odds ratio =(More)
The first Salmonella Enteritidis phage type (PT) 1 infection in a commercial layer flock of 2700 birds in Finland occurred in 1995. All the birds were ordered to be killed, the eggs to be destroyed and access to the layer house was denied in order to prevent spread of the infection. Ninety one commercial layers, 61 replacement pullets and 1062 eggs were(More)