Contaminant exposure and effects in Baltic ringed and grey seals as assessed by biomarkers.

The Baltic Sea ecosystem has suffered from a heavy pollutant load for more than three decades. Persistent organic pollutants (POPs) and heavy metals have been of most concern due to their persistence and toxic properties. Ringed seals (Phoca hispida baltica) and grey seals (Halichoerus grypus) living in the Baltic Sea have been suffering from pathological impairments, including reproductive disturbances, which have resulted in a depressed reproductive capacity. We investigated several biochemical parameters as potential biomarkers for exposure to and effects of the contaminant load in the Baltic seals. Seals from less polluted areas were used as reference material in terms of the pollution load. In both Baltic seal populations, the levels of some biochemical parameters diverged from those in the reference seals, and some of these showed a clear correlation with the individual contaminant load. Of the potential bioindicators, we propose cytochrome P4501A activity and vitamin E levels, in blubber or plasma, as exposure biomarkers for polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT) in both species. The arylhydrocarbon receptor-mediated chemical-activated luciferase gene expression (CALUX) response reflects the whole PCB and DDT burden in ringed seals. Retinyl palmitate (vitamin A) levels showed a negative correlation with the individual POP load, and is proposed as potential effect biomarkers for the depletion of the vitamin A stores. As the nutritional levels of both vitamin A and E have an impact on the vitamin levels in the seals, more information on the dietary vitamin levels is needed before any conclusions can be drawn. As the relationship between biochemical parameters and contaminants varied between the two species, species-specific characteristics has to be considered when monitoring the health status and possible toxic effects of the contaminant load in ringed and grey seals.

Survival of Yersinia enterocolitica in Fermented Sausages Manufactured With Different Levels of Nitrite and Different Starter Cultures.

The ability of Yersinia enterocolitica 0:3 to grow and survive during the manufacture of fermented sausages made with 0, 50, 80, 100, and 120 mg/kg added sodium nitrite and three different commercial starter cultures was determined. The sausage mass was inoculated to contain 1.7 × 105 of Y. enterocolitica per g. Yersinia was not detected after 28 d in sausages made with 80, 100, or 120 mg/kg of sodium nitrite. All sausages manufactured without or with 50 mg/kg sodium nitrite harbored Yersinia during the test period of 35 d. The highest level of Yersinia (5.9 log10 CFU/g) was detected in sausages made with no sodium nitrite and with Pediococcus acidilactici ©. In sausages made with Lactobacillus pentosus (A), the level of Yersinia was less than 2.0 log10 CFU/g. In sausages made with Lactobacillus plantarum (B) and 50 mg/kg sodium nitrite, the level of Yersinia was 2.9 log10 CFU/g. The pH values made with starters A, B, and C reached the pH values of 4.9, 5.2, and 5.4, respectively.