Need to Know

• EFSA identified five of eight Alternaria mycotoxins found in food and feed as genotoxic: Alternariol (AOH), alternariol monomethyl ether (AME), altertoxin I (ATX-I), altertoxin II (ATX-II), and stemphyltoxin III (STTX-III)
• Dietary exposure to AOH and AME exceeded the threshold of toxicological concern (TTC) for substances with potential DNA-damaging and/or carcinogenic properties in most population groups, warranting further risk assessment
• Tenuazonic acid (TeA) was the most frequently quantified Alternaria toxin in food, and while EFSA concluded that adverse effects from its non-genotoxic activity were unlikely at current dietary exposure levels, its genotoxic potential remains unclear
• Infants, toddlers, and other young children generally had the highest estimated dietary exposure relative to body weight, with major contributing foods including cereal-based products, fruit products and juices, tomatoes, vegetables, and vegetable oils
• Significant data gaps remain regarding animal health risks and combined exposure to Alternaria toxins, warranting further toxicological research, improved analytical methods, and continued monitoring of food and feed

Alternaria toxins are mycotoxins produced predominantly by fungi of the genus Alternaria, particularly A. alternata. These fungi can contaminate a range of agricultural commodities, including fruits, vegetables, cereals, and oilseeds.

The assessment covered eight toxins: alternariol (AOH), alternariol monomethyl ether (AME), altenuene (ALT), altertoxin I (ATX-I), altertoxin II (ATX-II), stemphyltoxin III (STTX-III), tenuazonic acid (TeA), and tentoxin (TEN).

Five Alternaria Toxins Identified as Genotoxic

EFSA concluded that five of the eight assessed toxins were genotoxic: AOH, AME, ATX-I, ATX-II, and STTX-III.

For AOH and AME, the panel determined that the toxins induce DNA damage through a non-threshold mechanism of action, meaning that scientists were unable to identify a level of exposure at which the possibility of harm can be completely ruled out. Estimated mean chronic dietary exposures to both toxins exceeded the threshold of toxicological concern (TTC) of 2.5 nanograms per kilogram (ng/kg) of body weight (bw) per day for substances with potential DNA-reactive mutagenic and/or carcinogenic properties in most population groups.

EFSA noted that a risk characterization approach other than the TTC would be needed to assess the risks associated with the genotoxicity of AOH and AME.

Although ATX-I, ATX-II, and STTX-III were also identified as genotoxic, insufficient occurrence data and toxicological studies prevented EFSA from characterizing the risks associated with dietary exposure to these substances.

Tenuazonic Acid Most Prevalent in Food, but Low Probability of Adverse Effects

TeA was the most frequently quantified Alternaria toxin in food, with the highest reported concentrations found in mulberries, paprika powder, and processed tomato products.

The assessment considered 57,104 analytical results from 16,283 food samples collected between 2015 and 2024, covering five toxins: AOH, AME, ALT, TeA, and TEN.

Among the foods analyzed, the highest mean TeA concentrations were reported in mulberries (14,373 micrograms per kilogram [μg/kg]) and paprika powder (11,650 μg/kg). Relatively high concentrations were also identified in processed tomato products, exceeding those found in fresh tomatoes.

Available toxicological evidence was insufficient to determine whether TeA is genotoxic. However, regarding its non-genotoxic effects, EFSA concluded with 98 percent certainty that dietary exposure would not exceed the TTC of 1,500 ng/kg bw/day for any population group, indicating a low probability of adverse health effects.

For ALT and TEN, which EFSA determined were not genotoxic, estimated dietary exposures were below the relevant TTC of 1,500 ng/kg bw/day. The panel therefore concluded that adverse health effects from exposure to these toxins were unlikely at current dietary exposure levels.

Young Children Had Highest Estimated Dietary Exposure

EFSA's assessment identified infants, toddlers, and other young children as the population groups with the highest estimated dietary exposure to Alternaria toxins relative to body weight.

The foods contributing most to exposure varied by toxin and age group, but included cereal-based foods, fruit products and juices, tomatoes, vegetables, grain-based products, and vegetable oils.

For TeA, estimated mean dietary exposure was highest among toddlers, ranging from 581–675 ng/kg bw/day, while the highest rate of exposure in the 95^th percentile was estimated among other children, at 1,811–1,925 ng/kg bw/day.

For AOH, the highest mean exposure was estimated among infants, while the highest 95^th-percentile exposure occurred among toddlers. For AME, both mean and high dietary exposures were greatest among other children.

EFSA noted that dietary exposure estimates were generally higher than those reported in its 2016 assessment. However, the increase was attributed to improved coverage of food categories in the available occurrence data, rather than evidence of increased Alternaria toxin contamination.

Animal Health Risks Remain Uncertain

EFSA determined that additional data are needed to characterize the risks of Alternaria toxins in feed for most animal species.

Based on available evidence, adverse health effects from dietary exposure to AOH and AME were considered unlikely for chickens raised for meat production at current feed concentrations.

However, potential health risks from TeA exposure could not be excluded for chickens raised for meat production or laying hens.

The assessment identified a lowest-observed-adverse-effect level (LOAEL) for TeA of 0.63 milligrams (mg)/kg bw/day, based on a 21-day oral exposure study in chickens. A conservative dietary exposure scenario, assuming a diet consisting exclusively of contaminated wheat, produced exposure estimates corresponding to approximately 10 percent of this LOAEL.

For other animal species and toxins, insufficient occurrence and toxicity data prevented a comprehensive risk characterization.

EFSA Calls for Additional Research and Monitoring

EFSA identified several data gaps requiring further investigation, including the occurrence, toxicological effects, and combined risks of Alternaria toxins in food and feed.

The panel recommended improving analytical methods and developing standards for toxins that cannot currently be reliably quantified, particularly ATX-II and STTX-III, as well as certain modified forms of Alternaria toxins.

Additional recommendations included continued monitoring of foods and feeds that contribute most to dietary exposure, further investigation of TeA genotoxicity, and research into the effects of food processing on toxin concentrations.

EFSA also explored the use of non-animal testing methods, combining in vitro data with physiologically based kinetic modeling, to estimate a dietary exposure level for TeA that would not be expected to cause adverse effects. However, remaining uncertainties prevented the results from being used in the final risk assessment.

The panel emphasized the need for additional toxicological and occurrence data to address remaining uncertainties and support future risk assessments, including evaluations of combined exposure to multiple Alternaria toxins.