In Northern Mato Grosso, which accounts for 27 percent of Brazil’s second corn crop output, in February of this year there was 21% more rain than the historical average, according to data from Somar and the Geographical and Statistical Brazilian Institute. This meant that growers were not able to harvest their soybeans in time, and led to postponed replanting of fields with corn. In March, it was predicted that the corn harvest of 2014 would be threatened by the return of rain to corn-growing regions.
A total of 34 corn and 23 soy samples from the current harvest season were screened for the presence of multiple mycotoxins and other secondary metabolites using Spectrum 380®, a method based on Liquid Chromatography coupled with tandem Mass Spectrometry (LC-MS/MS). This state of the art technique developed at the hot spot for mycotoxin investigation the IFA-Tulln based in Austria, enables the detection of more than 380 metabolites in one go. This unique method not only includes the most commonly found mycotoxins but also allows the detection of other less known metabolites and provides the full picture of toxic load in the sample.
The multi-mycotoxin analysis is a tool that is changing the way we see mycotoxin contamination. Previous methods which focused on the main mycotoxins in agricultural commodities included only aflatoxins (Afla), deoxynivalenol (DON), zearalenone (ZEN), ochratoxins (OTA) or fumonisins (FUM) in the analysis. According to our long term experience in the field of mycotoxins and our 10 year Mycotoxin Survey program, DON and FUM are worldwide the most prevalent substances found in agricultural commodities.
Fumonisins compromise Brazilian corn quality
A total of 20 metabolites were found in over 60% of the Brazilian corn samples, the majority of these substances are produced by Fusarium species. As expected, fumonisins are the main concern in Brazilian corn. Fumonisin B1, B2 and B4 were present in all corn samples at average concentrations of 3664 ppb FB1, 1472 ppb FB2 and 563 ppb FB4. Also fumonisin B3 was detected in over 90% of these corn samples. Total fumonisins were present in 65% of all corn samples at levels above 1000 ppb, a concentration that poses a possible risk for most livestock animals.
ZEN was detected in 68% of the corn samples at an average concentration of 265 ppb, a level that may pose a risk to breeding and young animals which are most sensitive to the effects of this mycoestrogenic substance.
Type B trichothecenes were present in 85% of the corn samples. The most common type B trichothecene was nivalenol with a prevalence of 85% at an average of 1021 ppb. DON was present in 29% of these samples at an average of 875 ppb. Conjugated DON in the form of DON-3-glucoside had a slightly higher prevalence as its parental form (32%) and its average concentration (178 ppb) represents 20% of DON. Total type B trichothecenes were present in 32% of the corn samples at levels above 200 ppb, a concentration that poses a high risk for piglets. Type A trichothecenes, such as T-2 toxin, show higher toxicity than type B trichothecenes. In total, 88% of the Brazilian corn samples contained T-2 toxin at relatively low concentrations.
Although aflatoxin B1 was only present in 20% of the samples, the average concentration was 181 ppb. This is a level considered to pose a health risk for most livestock animals, especially dairy cattle, which show highest sensitivity.
Zearalenone and its metabolites are common in Brazilian soy
Soy samples showed lower levels of contamination compared to corn samples. However, a total of 12 metabolites were found in more than 60% of the soy samples. These metabolites include some emerging mycotoxins such as beauvericin (present in all soy samples), which has been currently taken into consideration as a potential risk factor for humans and animals by the European Food Safety Authority (EFSA).
As expected in soy, ZEN was present in a high number of samples (78%). Alpha-zearalenol, which is approximately 10 times more estrogenic than ZEN, was detected in 34% of the soy samples. Beta-zearalenol and conjugated ZEN (ZEN-sulfate) were present in 17% of these samples.
An important advantage of multi-mycotoxin analysis is the detection of normally undetected masked mycotoxins, as for instance more than 50% of deoxynivalenol are thought to exist in commodities in a masked form. Performing multi-mycotoxin analysis also allows the evaluation of the occurrence of mycotoxins which are not commonly measured and may be posing a threat to the animal. The effects of such mycotoxins on health and performance of humans and animals still need to be elucidated.