WASHINGTON, DC – Climate change will pose a number of challenges to food safety in the coming decades, from boosting the rates of food- and water-borne illnesses to enabling the spread of pathogens, researchers reported Monday at the annual meeting of the American Association for the Advancement of Science.
Depending on the greenhouse gas emissions scenario, global average temperature is expected to rise between 1.1° and 6.8° Celsius by the end of the century. And warmer temperatures are known to increase rates of some diseases: According to a recent study of salmonellosis in Europe, frequency of the ailment rises about 12 percent for every 1°C that air temperature increases beyond a baseline of 6°C, said Cristina Tirado, an environmental scientist at the University of California, Los Angeles. The precise cause for this trend isn’t clear, said Ewen Todd, a bacteriologist at Michigan State University in East Lansing. It’s possible that warmer temperatures cause bacteria to grow more quickly, or people may prepare food differently in warmer weather (grilling outdoors vis-à-vis cooking in a kitchen, for example).
Climate change can increase disease risks in several ways, Tirado added. The concentration of methyl mercury in fish increases about 3.5 percent for every 1°C rise in water temperature. Warmer sea-surface temperatures can boost the frequency of harmful algal blooms, leading to an increased incidence of paralytic shellfish poisoning. Higher water temperatures also enable the spread of pathogens to higher latitudes: An outbreak of vibriosis on an Alaskan cruise ship in 2005, later linked to oysters that had been harvested near one of the ship’s ports of call, represents the spread of the disease-causing Vibrio parahaemolyticus to a locale more than 1,000 kilometers north of its previous known range. Dust storms, which are expected to increase in some regions due to climate change, could wreak their own havoc, because iron-rich mineral dust can drive a 10- to 1,000-fold increase in the growth rate of Vibrio bacteria.