NUTRIAD Spain 2017 mycotoxin survey in maize

Author: Radka Borutova; Business development manager at NUTRIAD International

Mycotoxins are a structurally diverse group of mostly small molecular weight compounds, produced mainly by the secondary metabolism of some filamentous fungi, or molds, which under suitable temperature and humidity conditions, may develop on various foods and feeds, causing serious risks for human and animal health (Dinis et al., 2007). Currently, more than 300 mycotoxins are known and scientific attention is mainly focused on those that have proven to be carcinogenic and/or toxic. Human exposure to mycotoxins may result from consumption of plant-derived foods that are contaminated with toxins, the carry-over of mycotoxins and their metabolites in animal products such as meat and eggs (CAST, 2003) or exposure to air and dust containing toxins (Jarvis, 2002).

2017 maize Belgium1

Picture 1: Maize harvested in Europe 2017 ©Copyright: Olga Averkieva, NUTRIAD International

The 2017 NUTRIAD Mycotoxin Survey included 121 maize samples from across Spain. All samples were collected almost immediately after the harvest from farms or animal feed production sites. Sample providers were advised to follow the principles of good sampling (Richard, 2000). Analytical personnel and/or laboratory staff were not involved in the sampling and did not influence any part of this procedure.

More than 480 analyses were conducted to test for the occurrence of the 4 mycotoxins most frequently found in agricultural commodities intended for animal production. The survey provided an insight into the incidences of aflatoxin B1 (AfB1), zearalenone (ZEN), deoxynivalenol (DON) and fumonisins (FUM) (sum of fumonisin B1 and fumonisin B2). 

All 4 mycotoxins were analyzed by Enzyme-Linked Immuno-Sorbent Assay (ELISA). For the purpose of data analysis, non-detection levels were based on the limits of quantification (LOQ) of the test method for each mycotoxin: AfB1 <1 μg/kg; ZEN <5 μg/kg; DON <74 μg/kg and FUM <222 μg/kg.


The results showed that almost 47% and 44% of the maize samples were contaminated with FUM and DON, respectively. Only 5,8% of the samples contained AfB1 and this low incidence of contamination was unexpected. The average concentrations of all recovered mycotoxins were medium (>LOQ but below EU recommendation levels). The highest concentration of DON detected in one of the samples reached 3090 μg/kg. Unexpectedly, 53% of the samples contained ZEN, a mycotoxin than can affect the fertility performance of all animal species.  This incidence is much higher in comparison to the previous year when only 8% of samples were positive for ZEN. Several samples were concurrently contaminated with 2 to 4 mycotoxins which may lead to synergistic interactions among them.

Table 1 – Mycotoxin contamination of maize in Spain 2017

Table 1 – Mycotoxin contamination of maize in Spain 2017

The unexpected results of this survey were the very high average concentration of AfB1 which reached 30 μg/kg and the maximum concentration of AfB1 which reached 115 μg/kg. Such high average and maximum concentrations of aflatoxin B1 in maize collected in Spain will be a definite concern in the Spanish market. Consequently, there may be a high level of the metabolite aflatoxin M1 in the dairy cows milk which could also be a concern . Both average and maximum aflatoxin B1 concentrations exceeded the maximum EU permitted concentration of aflatoxin B1 (20 μg/kg) in feed materials (COMMISSION REGULATION (EU) No 574/2011).

Figure 1 – Percentage of positive samples (>LOQ)

The correlation between DON and ZEN that looked high at the beginning, was not confirmed by the correlation analysis (R2=0.1518).


The NUTRIAD 2017 mycotoxin survey concluded that the year’s harvest of maize in Spain was of medium quality (>LOQ but below EU recommendation levels) in terms of mycotoxin contamination (DON, ZEN, FUM). The exceptions were the very high average and the maximum concentrations of aflatoxin B1 which clearly exceeded the concentration of aflatoxin B1 permitted in the EU in feed materials.  Due to the unexpected very high average and maximum concentrations of aflatoxin B1, the 2017 maize crop in Spain should not be considered safe for inclusion into finished feed rations for dairy milk producers and a degree of vigilance is prudent.

Vigilance is always advisable as cereals in animal feeds originate from many sources.  Some continental European cereals and South American soya harvested in 2017 have been shown to be contaminated with medium to high concentrations of mycotoxins. The last possible line of defense is the detoxification of mycotoxins in vivo. The addition of proven mycotoxin deactivators to animal feeds is a very common method to prevent mycotoxicosis and is an effective strategy to keep mycotoxin risk low under any and all conditions.

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CAST, Mycotoxins: Risks in Plant, Animal and Human Systems. Report No. 139 Council for Agricultural Science and Technology, Ames, Iowa, USA (2003).

Dinis A.M.P., C.M. Lino, A.S. Pena Ochratoxin A in nephropathic patients from two cities of central zone in Portugal J. Pharmaceut. Biomed. Anal., 44 (2007), pp. 553-557.

Jarvis, B.B., Chemistry and toxicology of molds isolated from water-damaged buildings. Mycotoxins and food safety Adv. Exp. Med. Biol., 504 (2002), pp. 43-52.

Richard, J., 2000. Sampling and sample preparation for mycotoxin analysis. Romer® Labs Guide to Mycotoxins. 2. Romer® Labs Inc., 1301 Stylemaster Drive, Union, MO, USA 63084-1156.

Published on Nutriad website on 02/03/2018