Aims: To investigate the presence of enterotoxigenic Staphylococcus aureus in bulk milk and in a selection of raw milk products. Methods and results: Samples of bovine (n = 220) and caprine (n = 213) bulk milk, and raw milk products (n = 82) were analysed for S. aureus. Isolates were tested for staphylococcal enterotoxin (SE) production (SEA-SED) by reversed passive latex agglutination and for SE genes (sea–see, seg–sej) by multiplex PCR. Staphylococcus aureus was detected in 165 (75%) bovine and 205 (96·2%) caprine bulk milk samples and in 31 (37·8%) raw milk product samples. Enterotoxin production was observed in 22·1% and 57·3% of S. aureus isolates from bovine and caprine bulk milk, respectively, while SE genes were detected in 52·5% of the bovine and 55·8% of the caprine bulk milk isolates. SEC and sec were most commonly detected. A greater diversity of SE genes were observed in bovine vs caprine isolates. Conclusions: Staphylococcus aureus seems highly prevalent in Norwegian bulk milk and isolates frequently produce SEs and contain SE genes. Enterotoxigenic S. aureus were also found in raw milk products. Significance and Impact of the Study: Staphylococcus aureus in Norwegian bovine and caprine bulk milk may constitute a risk with respect to staphylococcal food poisoning from raw milk products.

Expanding lead-based bullets, commonly used for hunting of big game, produce a scattering of lead particles in the carcass around the wound channel. Trimmings around this channel, which are sometimes fed to dogs, may contain lead particles. The aim of this study was to assess potential health effects of feeding dogs such trimmings. Lead ingestion most commonly causes gastrointestinal and neurological clinical signs, although renal, skeletal, haematological, cardiovascular and biochemical effects have also been reported. Experimental data indicate that a daily dose of around 1 mg lead as lead acetate/kg body weight for ten days may be considered as a Lowest Observed Effect Level in dogs. Acute toxicity documentation from the Centers for Disease Control and Prevention indicates 300 mg/kg body weight as the lowest dose of lead acetate causing death in dogs after oral ingestion. Our assessment suggests that dogs fed trimmings of lead-shot game may be affected by the amounts of lead present, and that even deadly exposure could occasionally occur. The intestinal absorption of lead from bullets was assumed to be 10–80 % of that of lead acetate, reflecting both the variability in particle size and uncertainty about the bioavailability of metallic lead in dogs. Despite data gaps, this study indicates that feeding dogs trimmings of lead-shot game may represent a risk of lead intoxication. More research is needed to assess the exact consequences, if lead-based bullets are still to be used. Meanwhile, we recommend that trimmings close to the wound channel should be made inaccessible to dogs, as well as to other domestic or wild animals.

In Europe, the incidence of invasive listeriosis has increased substantially during the last decades. We here present data from 289 listeriosis cases reported in Norway during the period 1977-2003, of which 12 cases were associated with 2 outbreaks and 39 cases were pregnancy-related. Medical records were obtained from 209 cases with listeriosis reported in 1977-2000. While the incidence of pregnancy-related listeriosis has remained stable at an average rate of 34 per million pregnant women per y during the period, the incidence of sporadic, non-pregnancy-related cases has increased from 1.1 to 3.7 per million per y. The present Norwegian incidence of reported cases is lower than in Denmark, but the case fatality rate is higher, indicating a possible under-reporting of mild listeriosis cases in Norway. We discuss how preventive measures, case identification and surveillance may have influenced listeriosis incidence in Norway.

The aim of this study was to investigate the bacteriological quality of strawberries at harvest and to study risk factors such as irrigation water, soil and picker’s hand cleanliness. Four farms were visited during the harvest season in 2012. Samples of strawberries, irrigation water, soil and hand swabs were collected and analyzed for E. coli, Campylobacter, Salmonella and STEC Although fecal indicators and pathogens were found in environmental samples, only one of 80 samples of strawberries was positive for E. coli (1.0 log₁₀ cfu/g) and pathogens were not detected in any of the strawberry samples. The water samples from all irrigation sources were contaminated with E. coli in numbers ranging from 0 to 3.3 log₁₀ cfu/g. Campylobacter (8/16 samples) and Salmonella (1/16 samples) were isolated from samples with high numbers of E. coli. The water samples collected from a lake had lower numbers of E. coli than the samples from rivers and a stream. The present study indicated continuous background contamination in the primary production environment. Although the background contamination was not reflected on the strawberries tested here, the results must be interpreted with caution due to the limited number of samples.

Gyrodactylus salaris is a major threat to wild populations of Atlantic salmon Salmo salar in Norway. Inter-river dispersal of this parasite is considered to be mainly linked to infested fish. Dispersal through movement of contaminated water is considered possible but has not been quantitatively evaluated. To approach this problem, we built a simple model to estimate (1) the water concentration of free-living G. salaris and (2) the probability that given water volumes would contain free-living parasites. The concentration was back-estimated from reported experimental observations on the number of salmon juveniles found to be infected after being caged in a heavily infested river in Norway, protected from direct contact with the substrate or fish. Monte Carlo simulation was used to account for uncertainty and variability. The average concentration of G. salaris in the water column during the experiment was estimated to be 0.12 m(-3) (95% CI = 0.05 to 0.24). The probability that a given volume would contain at least 1 parasite was 1.2 x 10(-4) (95% CI = 5 x 10(-5) to 2.4 x 10(-4)) for 1 l, increasing to 0.67 (95% CI = 0.39 to 0.91) for 10,000 l. Thus, only high volumes were likely to represent a significant risk. Since we used data from a heavily infested spot, and despite the fact that time and space variations in water concentration of G. salaris may occur, we conclude that the risk of inter-river dispersal due to transfer of infested water through common river activities by humans is probably low.