During the holiday season, consumers are particularly keen to reach for dried fruits and nuts: nuts, dried fruits, cake mixes, muesli and “healthy snacks”. These products are associated with naturalness, high quality and family tradition, which is why expectations for their safety are particularly high. At the same time, it is precisely in this product category that the risk of chemical contamination lurks, such as: heavy metals and mycotoxins, which, although invisible to the naked eye, can have real consequences for consumer health and producer reputation.
Why Do Heavy Metals and Mycotoxins Appear in Dried Fruits and Nuts?
Heavy metals such as lead, cadmium, inorganic arsenic and mercury are present in the natural environment and can enter food from contaminated soil, water, air or feed. In dried fruits and nuts, they appear primarily as a result of absorption of heavy metal compounds by plants from contaminated environments. The drying process causes an increase in the concentration of these contaminants, which can further lead to exceeding safety standards in the final product.
Mycotoxins are toxic metabolites of molds that develop on plant raw materials when cultivation, drying or storage conditions are not met. In the case of dried fruits and nuts, aflatoxins (especially B1) produced by Aspergillus fungi, mainly of the species flavus and parasiticus, and ochratoxin A produced by fungi of the genus Aspergillus and Penicillium are particularly important.
A common feature of heavy metals and many mycotoxins is that health effects can result from long-term exposure to small doses, rather than from single high exposures. From the producer’s perspective, this means the need for continuous control, not one-time verification.
EU Regulations: What Do the Regulations Require?
The content of chemical contaminants in food, including in dried fruits and nuts, is regulated primarily by Commission Regulation (EU) 2023/915 and its subsequent amendments. This document specifies the maximum allowable levels for, among others: heavy metals and selected mycotoxins in individual food groups.
In the area of heavy metals, particularly important for dried fruits and nuts are the limits for cadmium and lead in nuts, oilseeds, dried fruits, cocoa and grain products. The regulations differentiate the values depending on the type of raw material.
With regard to mycotoxins, the regulation defines, among other things, the allowable levels of aflatoxin B1 and the sum of aflatoxins in nuts and dried fruits intended for direct consumption, as well as separate thresholds for raw materials subject to sorting or other physical processing. The situation is similar in the case of ochratoxin A in dried fruits and nuts – different values apply to raw materials and different to finished products on store shelves.
When developing quality specifications for raw materials and finished products, it is crucial to refer each time to the current wording of the regulation and its annexes, as the limit values may change with new risk assessments.
Where Do Mycotoxins Come From in Dried Fruits and Nuts?
Mycotoxins do not appear “out of nowhere” – they are the result of the development of specific mold species on the raw material. In practice, their development most often occurs when:
- crops of nuts or fruits mature or are left in the field under conditions conducive to moisture accumulation,
- the drying process is too slow or conducted at inappropriate temperatures,
- raw material is stored too long in silos or warehouses with elevated humidity,
- water vapor condensation occurs in containers and collective packaging during transport.
In the case of dried fruits and nuts, an additional challenge is the long supply chain – often including cultivation outside the EU, long transport, repackaging and mixing of raw materials from different sources. This means that the level of mycotoxins is influenced not only by the producer of the final mix, but by every participant in the supply chain – from the farmer, through the dryer and warehouse, to the distributor.
Heavy Metals in Dried Fruits and Nuts: Environment and Supply Chain
Heavy metals enter raw materials primarily from soil and water, in which trace but persistent amounts are present. They can also come from industrial emissions, historical contamination of agricultural land or improper waste management in crop cultivation areas.
In the production of dried fruits and nuts, the risk increases when:
- raw materials come from regions with elevated environmental contamination,
- there is no systematic verification of new suppliers for heavy metal content.
This is why supplier assessment, testing of raw materials upon receipt and periodic audits become an element of real risk management, not just a formality of the quality department.
How Are Heavy Metals and Mycotoxins Tested in Dried Fruits and Nuts?
The determination of heavy metals requires the use of sensitive techniques that allow detection of very low concentrations in complex matrices such as nuts or dried fruit mixes. In practice, inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP-OES) are mainly used, allowing simultaneous determination of multiple elements in a single sample.
At J.S. Hamilton, we analyze mycotoxins mainly using liquid chromatography coupled with mass spectrometry (LC-MS/MS). It is important to take a representative sample and prepare the sample for testing, taking into account the heterogeneity of such products as nut and dried fruit mixes, so that the result truly reflects the level of contamination in the entire batch.
What Do Test Results Mean for Dried Fruit and Nut Producers?
For producers, importers and store brands, test results are not just numbers in a test report – they are concrete risk management tools and a way to build competitive advantage. They allow:
- confirming the safety and compliance of batches with EU legal requirements,
- monitoring the stability and repeatability of processes over time,
- quickly identifying the source of the problem (raw material, warehouse, transport) and implementing corrective actions,
- communicating to customers and trading partners a real, not declarative approach to food safety.
In the dried fruits and nuts segment, and particularly intensively rotating during the holiday season – regular testing of heavy metals and mycotoxins is not just about meeting formal requirements. It is an investment in consumer trust, brand protection and a smooth holiday season, when nobody has time for quality crises.
J.S. Hamilton offers accredited testing of heavy metals and mycotoxins in dried fruits and nuts and other food products, supporting producers in meeting EU legal requirements and securing the holiday season in terms of quality and safety.