Global Warming Can Cause Food Poisoning

Posted in Food Policy,Food Safety,Our Blog on February 25, 2019

Global warming is not a myth, but rather a harsh reality. It’s repercussions on mankind are obvious and one of them is an increase in the number of food poisoning cases. Global warming causing food poisoning? You would be surprised.

A recent study published in Royal Society Open Science has proved that as the temperature of the planet heats up, we humans can become more vulnerable to food poisoning. The study was done by a team of researchers from University of Guelph and University of Toronto who showed that models of fly population increases as the temperature increases and why this can cause a surge in the number of food poisoning cases.

If greenhouse gas emissions continue to rise at the rate as they are today, these swarms of disease-ridden flies could double or even triple in the coming decades. The reason being global warming temperatures forming perfect condition for the insects to grow.

In this recent study, Canadian scientists looked at the cumulative effects this could have as fly-borne diseases become more widespread.

Campylobacter is a group of bacteria that is responsible for a large number of food poisoning cases annually. They are one of the most common causes of food poisoning along with Salmonella, Listeria, E.Coli, and Norovirus. The most common strain of bacteria that causes illnesses are C.jejuni and E.coli. The pathogens spread mostly through contaminated food mainly poultry and unpasteurized milk. The main reservoir of the pathogen is chickens.

Despite its prevalence, it is still not clear ‘exactly’ how they spread through populations. Campylobacteriosis infects people more in summers than any other season, when the flies are also more prevalent. As fluctuations in infections coincide with peak fly densities in summers, insects are considered to be a main vector in their transmission through human population. The bacteria has been found on the flies and therefore, they are thought to be transferred through domestic animals and food when the flies are buzzing around in their search for food.

Researchers used this information to explore the consequences when more flies appear in Canada as the planet warms up.

“Insects are very sensitive to changes in the weather and thrive in warmer temperatures” said Melanie Cousins, a PhD student who completed this study as a part of her master’s thesis at the University of Guelph. When the temperature increases, eggs hatch faster which means that fly population can increase drastically, she added. Therefore, when temperature will rise and length of the summers will increase, housefly population will benefit.

To dig a little deeper into the study, researchers built a model that imitated fly population numbers in Canada over the past 12 years and then used it to forecast population changes in the future. They used data on illness rates in the past 12 years to maintain accuracy. The model showed that cases of Campylobacter could double by 2080 if greenhouse gas emissions continued to be high.

A separate study published recently showed that intensive agriculture and pesticides can cause global insect populations to decrease to such a level that they can be eliminated within a century.

However, the author of this Canadian study predicted fly population for species like house flies, which are more adaptive and resilient to pesticides. They can survive even when the temperatures soar and while their competitors and possible predators are driven to near extinction.

Other studies that have linked global warming & food poisoning….

In 2018, a report from Nutrition Action Health letter showed that the levels of two foodborne pathogens – Vibrio and Cryptosporidium – are increasing as a result of climate change. Their prevalence has already increased in the last 50 years. This study basically has put a question mark on the age old adage of ‘not eating oysters in the months that contain the letter R’.

The same research also predicted that climate changes have caused the Vibrio bacteria to spread further North. Moreover, heavy rainfall as a result of climate change can also wash these pathogens from contaminated soil and bring them into ground water and drinking water.

Another study released in 2012 by European Center for Disease Prevention and Control showed that climate changes can impact outbreaks. Pathogens under review include Campylobacter, Salmonella, Listeria, Norovirus, Cryptosporidium and non-cholera Vibrio. The first two showed the strongest associations with climate change.

In 2010, a report from WHO and Malta’s Infectious Disease Prevention and Control Unit showed climate change in Maltese islands is increasing the likelihood of foodborne illnesses in the archipelago. The study found that there were 450 cases of diarrheal illnesses daily which peaked in May due to rise in temperatures. A similar study done in US in 2014 showed that Salmonella infections increase in the country with rising temperatures, more so in the Southern states of Alabama, Tennessee and Mississippi.

Some other climate change effects that can increase foodborne illnesses:

• Bacterial Adaptation: When bacteria becomes exposed to unfavorable environment, they try to adapt to it by developing a survivor mechanism. So, over the time, bacterial resistance might increase.
• Flooding: As a result of climate change, flash floods can cause contaminated soil to mix with groundwater and drinking water.
• Food Safety in emergencies: With sudden climate changes, we need quick reforms to prevent foodborne illness at this time, supply safe water and food and also manage the after-effects by delivering prompt response to foodborne diseases along with providing food safety education to the general public.
• Soil Contamination: Climate change can increase the periods of floods and droughts. This can cause agricultural contamination and hence, food contamination.

However, not all hope should be lost. Some studies have shown that consistent efforts by mankind can help in reducing the global warming and its effects on the planet. With public health efforts, we can reduce the infection rates from these pathogens, which suggests that with continuous endeavor we can counteract climate change’s impact in this area successfully.

By: Pooja Sharma, Contributing Writer (Non-Lawyer)