Unsafe food may sometimes only lead to mild acute symptoms but it can also cause chronic illness like cancers, or affect nutritional intake, according to experts.  

A webinar was held discussing the burden of contaminated food as part of the World Health Organization’s (WHO) Health Talks around World Food Safety Day today.

The event touched on a range of health consequences because of unsafe food caused by microbiological hazards such as bacteria, viruses, parasites, as well as chemicals and toxins. It also covered how WHO tries to quantify the burden through the estimation of total incidences, deaths, and disability-adjusted life years (DALYs).

WHO’s Foodborne Disease Burden Epidemiology Reference Group (FERG) published estimates in 2015 using 2010 data. Updated figures will be released in 2025 but the reference year has not yet been decided, with the influence of the COVID-19 pandemic being taken into account.

Dr. Rob Lake, chair of FERG for 2021 to 2025, said foodborne infections cause considerable mortality and morbidity.

“Foodborne disease is complex, there are a large number of different hazards, different health outcomes and effects occur on different timescales. Another complicating factor is that food is not the only transmission pathway, so we need to assess different pathways of exposure. We are often working with limited amounts of data.”

Draw attention to topic and don’t neglect parasites
Lake said the next estimates intend to include a greater number of chemical hazards to better represent this category.

“The chemicals and toxins task force is working hard to address this issue. We should remember that often people think of food poisoning as being a diarrheal or enteric disease but there are a large number of other hazards and these can cause quite different health outcomes as a result of foodborne exposure,” he said.

“Overall, our hope is the estimates will be useful for food regulators and decision makers and helpful in the setting of food safety policy. It also helps give prominence to the issue of foodborne disease and hopefully stimulates countries to develop improved food safety systems, risk management programs and good manufacturing practices. Essentially, until we can measure the impact of these diseases, it is very difficult to impress upon people how important they are.”

Dr. Lucy Robertson, from the Norwegian University of Life Sciences, said it was important the impact of parasites is not overlooked.

“Parasites are complex and come in all shapes and sizes. Foodborne parasites are often neglected. There is a huge diversity of protozoa, worms and flukes and the human burden is high. Often associated with numerous long term serious or chronic conditions, for many symptoms are severe, potentially fatal. They are also often associated with disadvantaged communities,” she said.

Robertson discussed cryptosporidium, saying transmission is not obvious due to the gap between infection and symptoms. Outbreaks in the EU and North America are often waterborne but treatment options for vulnerable groups are limited.

Another example was Trypanosoma Cruzi, the cause of Chagas disease. It was not included in the first set of FERG estimates but increasing reports of foodborne transmission include outbreaks due to juice made from açaí berries contaminated by infected reduviid bugs.

Enteric infections and chemicals
Dr. Tesfaye Gobena, of Haramaya University in Ethiopia, presented the burden of enteric diseases from the estimates published in 2015.

“The problem disproportionately affects children, pregnant women, the elderly and immuno-compromised individuals. Pathogens cause acute gastroenteritis including diarrhea, vomiting and abdominal discomfort. In addition, there are other serious long term outcomes such as Guillain-Barre Syndrome, Hemolytic Uremic Syndrome (HUS), reactive arthritis and stunting,” he said.

“Food safety remains a challenge at global level, particularly in low and middle income countries. Unsafe food has severe health, social and economic consequences. Interventions need to start at a local level. Continuous estimates of enteric foodborne disease is crucial to prioritize problems and to adequately inform policymakers.”

Dr. Lea Sletting Jakobsen, from the Technical University of Denmark, spoke about harmful chemicals in foods, including aflatoxin and dioxins.

Food can be contaminated in different ways including via naturally occurring contamination, food contact materials, pollution or processing practices. Health outcomes and severity vary such as liver cancer for aflatoxin and male infertility for dioxins.

“There is a general consensus that the burden due to chemicals, not only from food, is underestimated. It is important to highlight that if no burden is estimated, it does not mean there is no burden. Instead, it means we are faced with significant data gaps,” she said.

“One of the reasons is rarely can a disease case be traced back to the causative agent. Many of the health effects are multi-causal and you have a long lag time from chronic exposures to disease onset. We are exposed to a multitude of chemicals and we have these combination effects. With FERG and in several other projects, the coverage of chemical burden is expanding. Many more compounds are being investigated with the aim to quantify the burden and doing this could direct future research.”

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