Are heavy metals an emerging risk in tomatoes and salad crops?

Heavy metals like cadmium (Cd) and lead (Pb) are well-known for their toxicity and ability to bioaccumulate in the body, posing long-term health risks. As a result, food safety regulations worldwide closely monitor the levels of these elements in food.

While fresh tomatoes have not historically been identified as a high-risk crop for heavy metal contamination, recent events have shifted the tide.

In September 2024, the Rapid Alert System for Food and Feed (RASFF) issued two notifications of high cadmium levels in tomatoes, raising concerns.

The first report, from Croatia, involved tomatoes from Bosnia and Herzegovina. The second, just a day later from France, reported high cadmium levels in cherry tomatoes originating from Italy.

This sudden appearance of two separate incidents in different countries, within the same month, is particularly troubling as cadmium contamination in tomatoes has not previously been flagged as a significant issue.

Is this an emerging issue or underreporting?

The close timing of these two notifications leads to important questions:

• Has this issue been missed before?​ It’s possible that fresh tomatoes have not been regularly tested for heavy metals. If the focus of testing has been elsewhere, this may be the first time cadmium contamination is being detected.
• Is this a new problem?​ The back-to-back reports suggest a potential emerging issue, with contamination in the tomato supply chain that has gone unnoticed until now.

Possible sources of contamination

There are several potential sources of cadmium contamination in tomatoes:

• Contaminated soil​: Industrial activities like mining or improper waste disposal can introduce cadmium into agricultural soils.
• Fertilisers and manures​: Commercial fertilisers, especially phosphate-based ones, can contain trace amounts of cadmium, which can accumulate in crops.
• Irrigation with contaminated water​: Industrial effluent and wastewater may introduce heavy metals into the soil and water sources used for agriculture.
• Air pollutants​: Airborne cadmium from industrial emissions or vehicle exhaust can settle on crops, contributing to contamination.

Climate events like flooding may also play a role. August 2024 saw widespread flooding across Europe, which could have redistributed contaminated waters into agricultural areas, increasing the likelihood of cadmium reaching crops like tomatoes.

Could fraudulent labelling be a factor?

Another issue to consider is the possibility of origin fraud. Mislabelling the origin of tomatoes could complicate efforts to trace the source of contamination. Croatia's earlier report (in August) of high cadmium in peppers from Bosnia and Herzegovina provides another line of enquiry to investigate. Further investigation into the true source of these tomatoes might be necessary.

Managing the risk of heavy metals

Given the potential seriousness of these reports, several steps could help mitigate future risks:

• Regular heavy metal testing​: Establishing baseline heavy metal testing for salad crops, including tomatoes, could help detect contamination earlier.
• Testing after extreme weather events​: Flooding and other extreme weather events can exacerbate contamination risks, making it critical to increase testing during these periods.

Cross-border collaboration between food safety authorities and agricultural sectors will be essential to identify the true source of contamination and prevent future incidents.

What now?

The recent cadmium contamination reports in tomatoes highlight the need for increased vigilance in monitoring heavy metals in the food supply.

Whether this is an emerging issue or the result of underreporting, as a new issue, it needs to be understood. This should be considered a risk until you have evidence it is not a problem within your supply chain.