There is little doubt that the Earth’s climate is getting warmer. According to the Intergovernmental Panel on Climate Change (IPCC), the mean global temperature over land and sea rose by 0.85oC between 1880 and 2012, while the period from 1983 to 2012 was probably the warmest 30 years in the last 1400. Why this is happening is more contentious, although the overwhelming weight of scientific evidence makes it pretty clear that human activity has a lot to do with it. Whether you believe that or not, there is no getting away from the fact that climate change will have consequences for our planet and for its inhabitants. Some of these consequences may be positive, but many will make life more difficult and will require us to adapt to changed world we will all be living in.
A number of attempts have been made to predict the effect rising temperatures will have on the safety of the food supply. The UN Food and Agriculture Organisation (FAO) published a report called Climate Change: Implications for Food Safety in 2008. The FAO report focused on foodborne disease, biotoxins and environmental contaminants and, while often speculative, it presented some worrying possibilities plausible enough to cause concern to those responsible for the safety of our food. For example, contamination of shellfish fisheries by marine biotoxins is likely to become more widespread as the distribution of the algae that produce the toxins expands and warmer conditions favouring algal blooms become more common.
Now comes a new warning that climate change may already be having an effect on seafood safety, not because of algal toxins but because of the spread of especially virulent strains of the foodborne bacterial pathogen Vibrio parahaemolyticus. Specialists from food safety and public health agencies in the USA and Europe have written a letter to the New England Journal of Medicine describing seafood-related outbreaks of food poisoning caused by these virulent strains, one in the eastern USA and one in northern Spain. This is unusual because up until 2012 these strains (O4:K12 and O4:KUT) had only ever been isolated from Pacific waters. Apparently, warmer than usual surface seawater temperatures in the regions where the new outbreaks occurred may have helped the bacteria survive and multiply to the levels needed to cause illness – outbreaks are always more common in the warmer summer months.
This may be an early indication that the food safety landscape is going to change significantly as the temperature rises. Threats once thought of as tropical may well become common in temperate regions in years to come. The food industry and food safety agencies worldwide need to be aware of the possibilities and try to avoid being taken by surprise. That will mean more surveillance of, and more research into, food safety threats emerging as a consequence of climate change. Early warning is always preferable to damage limitation.