Food contaminated by furan: what are the risks?

Furan is formed during the cooking of food and is recognized as a possibly carcinogenic by the International Agency for Research on Cancer. Coffee and ready-to-eat baby food contain the highest concentrations as they are prepared in closed environments. While this certainly gives cause for concern, the work of researchers at the University of Liege shows that the risks for the Belgian population are limited.

What we eat has a direct impact upon our health. Food safety, and more particularly food hygiene is today identified as one of the great challenges facing societies on a European and world-wide scale. Even if we can freely choose the food we eat, its exact composition - and therefore the possible presence of harmful products – is unknown to ordinary people. Fortunately, the authorities monitor and depend on scientists so that they can establish norms that must be respected in order to protect the consumer from the potentially harmful effects of some products.

Contaminants linked to transformation processes are part of the hidden components where their presence in the most common foodstuffs is often unknown by the consumers. It concerns undesirable and harmful substances formed during the preparation of foodstuffs. This kind of contaminant started to be monitored after the discovery of acrylamide in food in 2002. Acrylamide forms naturally in certain foods that are browned on the pan or fried, such as crisps and French fries, but also biscuits, cereals and bread. Since its discovery, this substance has been classed as “possibly carcinogenic for humans” by the International Agency for Research on Cancer (IARC) of the World Health Organization (WHO). A list of indicative values for acrylamide levels in various foodstuffs established by the European Union is currently available.

Coffee and small jars of baby food are the main culprits with regard to levels of furan content.

No regulation has already been established for furan, another contaminant linked to food transformation. Although classified as a probable carcinogenic substance by the IARC, the authorities are awaiting the results of supplementary scientific tests in order to establish levels of the chemical that should not be exceeded in foodstuffs. The first studies on furan date back to 2004-2005 and researchers at Ulg have been studying the chemical since 2008. In his doctoral thesis (1), financed by the Federal Public Health Service, the FPS Public Health, Food Chain Safety and Environment, Georges Scholl was asked with determining the level of contamination of foodstuffs in Belgium and the level of furan to which the adults, children and babies of our country are exposed.

Furan is a small organic molecule (C₄H₄O) formed during heat treatment as cooking or sterilization process of food. It is a very volatile molecule that is formed in the presence of many precursors such as amino acids, sugars, lipid oxidation of unsaturated fatty acids. It is found in pre-packed foods that have undergone heat treatment, like the contents of some food cans or glass jars but also vacuum-packed foods that are ready to eat.

The two foodstuffs with the highest levels of furan are roasted coffee and small jars of baby food! “Purees and stewed fruit for babies are produced in a controlled atmosphere to prevent against bacterial proliferation”, explains Georges Scholl, head of the Contaminants unit at the Center for Analytical Research and Technology (CART) at ULg. This method of preparation keeps the furan in the food. “, Any kind of food that is cooked or roasted may contain high levels of furan, especially when foods are sealed in airtightened packaging” continues Georges Scholl.

A narcotic and genotoxic substance

Furan was added to the list of compounds classed as possibly carcinogenic based on toxicological studies performed on rats. “Toxicologists highlighted that rats exposed to furan have developed cancers, such as cholangiocarcinomas and liver cancers”, points out Georges Scholl.  “In high concentrations, furan is narcotic and at lower concentrations it is genotoxic”, the researcher continues. In background exposure the scientist is referring specifically to quantities of furan ingested over a long period of time during normal long-term consumption of various “contaminated” foods. In reality, it is not the furan molecule itself that causes the problem but rather its major metabolite produced in the liver.

In order to assess the exposure of the Belgian public to furan, Georges Scholl, supervised by Professors Gauthier Eppe and Edwin De Pauw (CART), Professor Claude Saegerman (Unit for Epidemiology Research and Analysis of Risks applied to veterinary sciences, UREAR-ULg), developed sensitive analytical methods able to measure very small levels of furan in food. The scientists also conducted a sampling plan of foodstuffs covering the entire country.  “We tested more than 500 samples taken between the Belgian coast and Arlon in order to define the levels of furan in the different types of foodstuffs” explains Georges Scholl. “Based on data  consumption habits we were able to determine the average level of exposure for the Belgian population”. According to the results obtained, the levels of exposure to furan in Belgium are slightly higher than the European average.

Ready-to-eat baby foods are not popular in Belgium

Overall, the results are somewhat reassuring. Exposure estimates were presented per age class toddlers, children and adults. Concerning adults, the researchers divided the Belgian population into three categories linked to the quantity of furan ingested: high risk, low risk and questionable risk. “Analysis of our data revealed that in Belgium no ones is in the high-risk category, around 10% of the population is in the low-risk category and 90% in the category where risk is questionable”, explains Georges Scholl. This study also shows that coffee consumption contributes greatly to exposure and risk of contamination by furan. Drinking one cup of coffee more or less on a daily basis can increase or reduce the quantity of furan ingested by up to 20% in a single day!

The researchers have shown that children’s foods are also among those that contain the highest levels of furan. “For example, orange juice in cartons or bottles contains a lot of furan”, reveals Georges Scholl. Finally, even though small jars of baby food are relatively contaminated, they have limited contribution to the exposure of babies. In fact, infant eating habits are very traditional in Belgium. According to the figures of Kind and Gezin (the equivalent of National Office Child in Flanders), parents  only use in average one jar of baby food  out of  three meals. “Parents who feed their children solely with jars of baby food are very rare in Belgium”, adds Georges Scholl.

Changing our habits in food preparation

The conclusions of this research pointed out that the situation in Belgium is not alarmist. “However, we must continue to monitor furan in foodstuffs in order to refine the potential risks.”, declares Georges Scholl. In addition to the results obtained during this study, the researchers made some recommendations to The FPS Public Health, Food Chain Safety and Environment. “It is difficult to take upstream action at the industrial production scale of foodstuffs, but we can work downstream when preparing our food and beverages ”, explains the scientist. “Furan is very volatile compound, it is advisable to shake or stir thoroughly the food in the open-air or in an area with adequate ventilation before eatingt”.  For instance, it is preferable to reheat the foods in a saucepan rather than in a microwave.

Today, the Belgian researchers would like to continue the research by examining the formation and elimination of furan in situ during cooking processes but also with the objectives to assess other pathways of exposure to this volatile molecule such as inhalation and breathing during contaminated food intake. This would better approximate the exposure of the Belgian population to furan but also to take a more integrated view of exposure.

(1) Belgian population exposed to furan: from analytical developments to risk assessment, Georges Scholl, doctoral thesis, 2013.