Climate change impacts on natural toxins in food production systems, exemplified by deoxynivalenol in wheat and diarrhetic shellfish toxins.

Climate change is expected to affect food and feed safety, including the occurrence of natural toxins in primary crop and seafood production; however, to date, quantitative estimates are scarce. This study aimed to estimate the impact of climate change effects on mycotoxin contamination of cereal grains cultivated in the terrestrial area of north west Europe, and on the frequency of harmful algal blooms and contamination of shellfish with marine biotoxins in the North Sea coastal zone. The study focused on contamination of wheat with deoxynivalenol, and on abundance of Dinophysis spp. and the possible relationship with diarrhetic shellfish toxins. The study used currently available data and models. Global and regional climate models were combined with models of crop phenology, mycotoxin prediction models, hydrodynamic models and ecological models, with the output of one model being used as input for the other. In addition, statistical data analyses using existing national datasets from the study area were performed to obtain information on the relationships between Dinophysis spp. cell counts and contamination of shellfish with diarrhetic shellfish toxins as well as on frequency of cereal cropping. In this paper, a summary of the study is presented, and overall conclusions and recommendations are given. Climate change projections for the years 2031-2050 were used as the starting point of the analyses relative to a preceding 20-year baseline period from which the climate change signal was calculated. Results showed that, in general, climate change effects lead to advanced flowering and harvest of wheat, and increased risk of contamination of wheat with deoxynivalenol. Blooms of dinoflagellates were estimated to occur more often. If the group of Dinophysis spp. behaves similarly to other flagellates in the future then frequency of harmful algal blooms of Dinophysis spp. may also increase, but consequences for contamination of shellfish with diarrhetic shellfish toxins are uncertain. Climate change will also have indirect effects on toxin contamination, which may be equally important. For example, the frequency of cropping of wheat and maize in north Europe was projected to increase under climate change, which will also increase the risk of contamination of the grains with deoxynivalenol. Risk managers are encouraged to consider the entire range of the predictions of climate change effects on food safety hazards, rather than median or average values only. Furthermore, it is recommended to closely monitor levels of mycotoxins and marine biotoxins in the future, in particular related to risky situations associated with favourable climatic conditions for toxin producing organisms. In particular, it is important to pay attention to the continuity of collecting the right data, and the availability and accessibility of databases. On a European level, it is important to stress the need for harmonisation of terminology and data collection.

Monitoring of Dinophysis species and diarrhetic shellfish toxins in Flødevigen Bay, Norway: inter-annual variability over a 25-year time-series.

The accumulation of phycotoxins in bivalve mussels associated with mussels feeding on toxic phytoplankton is a well-known phenomenon in Norway. Regular monitoring for 25 years has revealed that accumulation of Diarrhetic Shellfish poisoning (DSP) toxins in mussels is the main phycotoxin problem along the Norwegian coast. The aim of this study was to evaluate possible trends over time of Dinophysis spp. and DSP as well as possible correlation between abundance of Dinophysis spp. and toxin accumulation in mussels, as based on intensive and regular monitoring at the southern coast of Norway at Flødevigen Bay. The main source organism causing a risk of DSP in Norway is Dinophysis acuta. However, it cannot be excluded that other Dinophysis spp., e.g. D. acuminata and D. norvegica, may contribute to the total accumulation of toxins. The variability in the occurrence of these species is high at both short- and long-term; between days and between years. There are, however, some important overall patterns in the occurrence of the species during the last decades. Dinophysis acuminata and D. norvegica have mainly been abundant from March to December, whereas D. acuta has typically occurred in late summer and autumn (August-December). For all three species we have observed a narrowing of the peak season since 2002 at the same time as they have become less abundant. Coincident with these changes, the problem of the accumulation of DSP toxins in mussels along the southern coast of Norway has declined significantly, but it is still mainly restricted to the autumn. Why the cell concentration of Dinophysis spp. has declined after 2002 is not obvious, but this has occurred in a period with relatively high summer temperatures. The relatively simultaneous changes in physical, chemical and biological factors of the pelagic ecosystem along the southern coast of Norway indicate that complicated ecological interactions may be involved.

Use of ELISA to identify Protoceratium reticulatum as a source of yessotoxin in Norway.

Picked cells of Protoceratium reticulatum collected from five locations in Norway were shown by ELISA analysis to contain yessotoxins (YTXs). The production of yessotoxin (YTX) was verified by culturing followed by LC-MS analysis of one of the Norwegian isolates. This is the first report of the biogenic origin of YTXs in Norway. The sensitivity of the ELISA method made it possible to quantitate YTXs in algal cultures, net-hauls, and in single cells of P. reticulatum. The cells picked from cultures and net-hauls contained 18-79 pg YTXs per cell. Dilution series and analyses of cells from non-YTX-producing algal species demonstrated the presence of only minimal matrix effects on the ELISA, probably attributable to the presence of salts. The sensitivity of this method makes it possible to search for other possible producers of YTXs, and might also make it possible to follow the YTXs through the food chain. This method allows, for the first time, measurement of the variability in toxin content within a population of dinoflagellate cells--rather than just the average amount of toxin per cell.