Zearalenone is a mycotoxin produced by some Fusarium species in food and feed. From a global perspective, Fusarium mycotoxins may be considered as metabolites of particular importance to animal health and productivity. The aim of this review is to collect and summarise information concerning the properties of zearalenone, its derivatives and their biotransformation. Data on the occurrence and toxicity of zearalenone and a comparison of analytical methods used in zearalenone identification and quantification will also be discussed. As our awareness and understanding of the risks associated with zearalenone exposure increase, some countries set official or recommended limits in certain commodities.

This study compares the susceptibility of winter wheat (Triticum aestivum L.) cultivars to Fusarium head blight (FHB) and accumulation of mycotoxins in kernels and chaff under different climatic conditions in two locations-Cerekwica near Poznan (Central West Poland) and Sitaniec, near Zamosc, Lublin region (South East Poland). Very high variations were found in the concentrations of mycotoxins (zearalenone, ZEA; nivalenol, NIV; deoxynivalenol, DON; moniliformin, MON) in examined fractions: Fusarium-damaged kernels (FDK) and healthy looking kernels (HLK) and in chaff for individual cultivars in both locations. In most cases, significantly higher concentrations of investigated toxins were recorded in wheat from the area of Lublin than from Poznan (p < 0.05). The highest Fusarium infection rates and mycotoxin biosynthesis levels were observed in the Lublin location, with the percentage of the FDK fraction ranging 8.1-81.6. In this region, ZEA concentration (microg g(-1)) after inoculation with F. culmorum and F. graminearum ranged from 0.02-0.48 and 0.32-1.04, respectively. In the Poznan area, the toxin concentrations were considerably lower, ranging 0.01-0.10 and 0.03-0.13 microg g(-1) for both isolates, respectively. The concentration of DON was significantly higher than ZEA or NIV levels. The levels of MON accumulation (microg g(-1)) in the FDK fraction were between 0.14 and 1.73 (Poznan area) and ND (not detected) to 2.51 (Lublin area). F. avenaceum infection rate ranged 7-35% in samples where the toxin was detected.

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High incidence of Fusarium head blight occurred in Northern and Southern Poland in the 2009 season. Head samples from 106 wheat fields were collected before harvest from Northern, Central and Southern Poland in August 2009. Fusarium species were identified in 1,311 heads with visible scab symptoms and the collected material was subjected to mycotoxin analyses. Fusarium graminearum was identified as the most frequently occurring species on wheat, present in 48% of all samples examined. This species prevailed in Northern and Southern Poland, with the frequencies of 53% and 55%, respectively, and its frequency has increased over five-fold after two decades. In the central part of the country, Fusarium culmorum was the major pathogen of wheat, with a frequency of 43%, although in this region the incidence of infected heads in wheat fields was lower than 1%. Several other species, including Fusarium avenaceum, Fusarium cerealis and Microdochium nivale, occurred with lower frequencies. Microscopic identification of species was confirmed using species-specific markers in DNA extracted directly from sporodochia. For the first time, glucosylated deoxynivalenol was identified in Polish cereals, in amounts of 1.6 to 7.4 mg/kg. Deoxynivalenol (DON) content was estimated between 1.7 and 11.9 mg/kg for the healthy looking kernels (HLK) fraction, while the Fusarium-damaged kernels (FDK) were contaminated with high amounts of DON, from 57.3 to 312.3 mg/kg, and zearalenone, from 0.035 to 4.48 mg/kg. The HLK fractions contained about 20 times less DON and zearalenone (ZEA) than the FDK fractions. ZEA accumulated in both FDK kernels and chaff fractions at a similar level. DON was accumulated in the chaff fraction in much lower amounts than in the FDK fraction.

Fusarium equiseti (Corda) Saccardo is a soil saprophyte and a weak pathogen, associated with several diseases of fruit and other crops in subtropical and tropical areas, but also in countries with temperate climate. A wide range of secondary metabolites has been identified among natural F. equiseti populations, with zearalenone (ZEA), fusarochromanone and fusarenon-X being the most common. In present study, the genetic diversity of strains from two populations (from Italy and Poland) was evaluated by analysing the translation elongation factor 1α (tef-1α) sequences, two polyketide synthases from the ZEA biosynthetic pathway (PKS13 and PKS4) and the TRI5 gene from the trichothecene biosynthetic pathway. ZEA was produced in rice cultures by 20 of the 27 tested isolates in concentrations ranging from 1.34 ng/g to 34,000 ng/g). The ability to produce enniatins and trichothecenes was evaluated in all strains by identifying esyn1, TRI13 and TRI4 genes. The presence of PKS4 and PKS13 genes was confirmed by polymerase chain reaction (PCR) in only some ZEA-producing isolates. Similarly, the TRI5 gene was found in 14 of the 27 isolates tested. This is likely to have been caused by the divergence of those genes between F. equiseti and F. graminearum (the latter species was used for the primers design) and can be exploited in phylogenetic studies. The analysis of the mycotoxin biosynthetic gene sequences can be used to differentiate the studied genotypes even more precisely than the analysis of the non-coding regions (like tef-1α).