Fusarium mycotoxins: The major food contaminants.

Mycotoxins, which are secondary metabolites produced by toxicogenic fungi, are natural food toxins that cause acute and chronic adverse reactions in humans and animals. The genus Fusarium is one of three major genera of mycotoxin-producing fungi. Trichothecenes, fumonisins, and zearalenone are the major Fusarium mycotoxins that occur worldwide. Fusarium mycotoxins have the potential to infiltrate the human food chain via contamination during crop production and food processing, eventually threatening human health. The occurrence and development of Fusarium mycotoxin contamination will change with climate change, especially with variations in temperature, precipitation, and carbon dioxide concentration. To address these challenges, researchers have built a series of effective models to forecast the occurrence of Fusarium mycotoxins and provide guidance for crop production. Fusarium mycotoxins frequently exist in food products at extremely low levels, thus necessitating the development of highly sensitive and reliable detection techniques. Numerous successful detection methods have been developed to meet the requirements of various situations, and an increasing number of methods are moving toward high-throughput features. Although Fusarium mycotoxins cannot be completely eliminated, numerous agronomic, chemical, physical, and biological methods can lower Fusarium mycotoxin contamination to safe levels during the preharvest and postharvest stages. These theoretical innovations and technological advances have the potential to facilitate the development of comprehensive strategies for effectively managing Fusarium mycotoxin contamination in the future.

Simultaneous determination of 17 regulated and non-regulated Fusarium mycotoxins co-occurring in foodstuffs by UPLC-MS/MS with solid-phase extraction.

Fusarium species produce numerous mycotoxins known to co-occur in food. While some of these mycotoxins (e.g., deoxynivalenol, fumonisins) are regulated in several countries, others are non-regulated (e.g., nivalenol, beauvericin). In this study, UPLC-MS/MS with solid-phase extraction cleanup was used to determine 17 Fusarium mycotoxins (FTs) simultaneously. The method showed excellent performance in terms of linearity (R2 > 0.99), LOD (<1.2 µg/kg), LOQ (<3.6 µg/kg), accuracy (70.0-116.3 %), repeatability (<15.7 %), reproducibility (<25.3 %), and expanded uncertainty (<41.7 %). The validated method was successfully applied to 198 marketed food samples collected in South Korea. Of the tested samples, 79 % were contaminated with at least one FT. Job's tears showed the highest prevalence of 14 FTs, and sorghum had the highest total FTs level (3.03 mg/kg). The results suggest that this method can be used for the simultaneous analysis of 17 FTs in food samples, which would serve as crucial information for risk management.

Traditional and emerging Fusarium mycotoxins disrupt homeostasis of bovine mammary cells by altering cell permeability and innate immune function.

High incidence of traditional and emerging Fusarium mycotoxins in cereal grains and silages can be a potential threat to feed safety and ruminants. Inadequate biodegradation of Fusarium mycotoxins by rumen microflora following ingestion of mycotoxin-contaminated feeds can lead to their circulatory transport to target tissues such as mammary gland. The bovine udder plays a pivotal role in maintaining milk yield and composition, thus, human health. However, toxic effects of Fusarium mycotoxins on bovine mammary gland are rarely studied. In this study, the bovine mammary epithelial cell line was used as an in-vitro model of bovine mammary epithelium to investigate effects of deoxynivalenol (DON), enniatin B (ENB) and beauvericin (BEA) on bovine mammary gland homeostasis. Results indicated that exposure to DON, ENB and BEA for 48 h significantly decreased cell viability in a concentration-dependent manner (P < 0.001). Exposure to DON at 0.39 µmol/L and BEA at 2.5 µmol/L for 48 h also decreased paracellular flux of FITC-40 kDa dextran (P < 0.05), whereas none of the mycotoxins affected transepithelial electrical resistance after 48 h exposure. The qPCR was performed for assessment of expression of gene coding tight junction (TJ) proteins, toll-like receptor 4 (TLR4) and cytokines after 4, 24 and 48 h of exposure. DON, ENB and BEA significantly upregulated the TJ protein zonula occludens-1, whereas markedly downregulated claudin 3 (P < 0.05). Exposure to DON at 1.35 µmol/L for 4 h significantly increased expression of occludin (P < 0.01). DON, ENB and BEA significant downregulated TLR4 (P < 0.05). In contrast, ENB markedly increased expression of cytokines interleukin-6 (IL-6) (P < 0.001), tumor necrosis factor α (TNF-a) (P < 0.05) and transforming growth factor-ß (TGF-ß) (P < 0.01). BEA significantly upregulated IL- 6 (P < 0.001) and TGF-ß (P = 0.01), but downregulated TNF-α (P < 0.001). These results suggest that DON, ENB and BEA can disrupt mammary gland homeostasis by inducing cell death as well as altering its paracellular permeability and expression of genes involved in innate immune function.

Accumulation of 4-Deoxy-7-hydroxytrichothecenes, but Not 4,7-Dihydroxytrichothecenes, in Axenic Culture of a Transgenic Nivalenol Chemotype Expressing the NX-Type FgTri1 Gene.

Fusarium graminearum species complex produces type B trichothecenes oxygenated at C-7. In axenic liquid culture, F. graminearum mainly accumulates one of the three types of trichothecenes, namely 3-acetyldeoxyinvalenol, 15-acetyldeoxyinvalenol, or mixtures of 4,15-diacetylnivalenol/4-acetylnivalenol, depending on each strain's genetic background. The acetyl groups of these trichothecenes are slowly deacetylated to give deoxynivalenol (DON) or nivalenol (NIV) on solid medium culture. Due to the evolution of F. graminearum FgTri1, encoding a cytochrome P450 monooxygenase responsible for hydroxylation at both C-7 and C-8, new derivatives of DON, designated as NX-type trichothecenes, have recently emerged. To assess the risks of emergence of new NX-type trichothecenes, we examined the effects of replacing FgTri1 in the three chemotypes with FgTri1_NX chemotype, which encodes a cytochrome P450 monooxygenase that can only hydroxylate C-7 of trichothecenes. Similar to the transgenic DON chemotypes, the transgenic NIV chemotype strain accumulated NX-type 4-deoxytrichothecenes in axenic liquid culture. C-4 oxygenated trichothecenes were marginal, despite the presence of a functional FgTri13 encoding a C-4 hydroxylase. At present, outcrossing of the currently occurring NX chemotype with NIV chemotype strains of F. graminearum in the natural environment likely will not yield a new strain that produces a C-4 oxygenated NX-type trichothecene.

Development and certification of a reference material for zearalenone in maize germ oil.

Zearalenone (ZEN), an estrogenic mycotoxin produced by several species of Fusarium fungi, is a common contaminant of cereal-based food worldwide. Due to frequent occurrences associated with high levels of ZEN, maize oil is a particular source of exposure. Although a European maximum level for ZEN in maize oil exists according to Commission Regulation (EC) No. 1126/2007 along with a newly developed international standard method for analysis, certified reference materials (CRM) are still not available. To overcome this lack, the first CRM for the determination of ZEN in contaminated maize germ oil (ERM®-BC715) was developed in the frame of a European Reference Materials (ERM®) project according to the requirements of ISO Guide 35. The whole process of CRM development including preparation, homogeneity and stability studies, and value assignment is presented. The assignment of the certified mass fraction was based upon an in-house study using high-performance liquid chromatography isotope dilution tandem mass spectrometry. Simultaneously, to support the in-house certification study, an interlaboratory comparison study was conducted with 13 expert laboratories using different analytical methods. The certified mass fraction and expanded uncertainty (k = 2) of ERM®-BC715 (362 ± 22) µg kg-1 ZEN are traceable to the SI. This reference material is intended for analytical quality control and contributes to the improvement of consumer protection and food safety.

Fate of Fusarium mycotoxins during processing of Nigerian traditional infant foods (ogi and soybean powder).

The influence of processing methods used to produce traditional Nigerian infant foods (ogi and processed soybean powder) on four European Union regulated Fusarium mycotoxins using naturally and artificially contaminated raw materials was studied using liquid chromatography-tandem mass spectrometry. Generally, there was a significant reduction of all the mycotoxins when compared to the initial concentration of the raw materials. Reduction in concentrations of the mycotoxins during ogi-processing started immediately after 36 h' steeping/fermentation for all the mycotoxins (fumonisin B1, zearalenone, deoxynivalenol, and T-2 toxin), and proceeded along the process chain (milling and sieving). In addition, deoxynivalenol-3-glucoside (16 ±â€¯3.2 µg/kg) and 3-acetyl-deoxynivalenol (9 ±â€¯5.5 µg/kg) initially absent in the raw maize were detected in the final ogi product. ß-zearalenol, hydrolysed fumonisin B1, and HT-2 toxin were also detected at varying concentrations. Regarding soybean processing, a similar trend was observed with fumonisin B1, zearalenone, deoxynivalenol, and T-2 toxin, irrespective of the method used or the initial concentration. Other mycotoxins detected in soybean product include 3-acetyl-deoxynivalenol, 15-acetyl-deoxynivalenol, deoxynivalenol-3-glucoside, HT-2 toxin, neosolaniol, α-zearalenol, ß-zearalenol, and zearalenone-14-glucoside. Although there was a reduction in the concentration of the free mycotoxin because of processing, other mycotoxins were detected in the products and thus, may present an additional health risk on consumers.

Hydrogen-Rich Water and Lactulose Protect Against Growth Suppression and Oxidative Stress in Female Piglets Fed Fusarium Toxins Contaminated Diets.

The objective of the current experiment was to evaluate whether hydrogen-rich water (HRW) or lactulose (LAC) could protect against the adverse effects of Fusarium mycotoxins-contaminated diet on the growth performance and antioxidant status in weaning piglets. A total of 24 individually housed female piglets were randomly assigned to receive four treatments for 25 days (six pigs/treatment): uncontaminated basal diet (negative control), mycotoxin-contaminated (MC) diet, MC diet + HRW (MC + HRW) and MC diet + LAC (MC + LAC). The plasma hydrogen levels before and after 2 h hydrogen-free water/HRW administration were detected at day 21, and the liver hydrogen levels were detected at the end of the experiment. Serum hormones related to appetite regulation, and serum and liver oxidant and antioxidant status were also measured at the end of the experiment. Results showed that both HRW and LAC treatments significantly attenuated the reduction of average daily gain (ADG) and average daily feed intake (ADFI) caused by Fusarium mycotoxins. LAC administration increased the hydrogen concentrations in plasma and liver. HRW treated group had higher plasma hydrogen levels than the MC group. Compared with the NC group, the MC group had significantly increased serum peptide YY (PYY) and cholecystokinin (CCK) levels. Interestingly, both HRW and LAC administrations had a lower reduced serum PYY and CKK levels. Most importantly, oral administration of HRW and LAC attenuated the Fusarium mycotoxins-induced oxidative stress. In conclusion, oral administration of hydrogen-rich water or lactulose could both protect against the growth reduction and oxidative damage caused by Fusarium mycotoxins.

Stability of fumonisin B1, deoxynivalenol, zearalenone, and T-2 toxin during processing of traditional Nigerian beer and spices.

The stability of the Fusarium mycotoxins fumonisin B1, deoxynivalenol, T-2 toxin, and zearalenone during processing of Nigerian traditional spices (dawadawa, okpehe, and ogiri) and beer (burukutu) using artificially contaminated raw materials was investigated. Results revealed the reduction of these toxins in all the final products. Boiling played a significant role (p < 0.05) in Fusarium mycotoxin reduction in the traditional spices. The highest percentage reduction of deoxynivalenol (76%) and zearalenone (74%) was observed during okpehe processing (boiled for 12 h). Dehulling and fermentation further demonstrated a positive influence on the reduction of these toxins with a total reduction ranging from 85 to 98% for dawadawa, 86 to 100% for okpehe, and 57 to 81% for ogiri. This trend was also observed during the production of traditional beer (burukutu), with malting and brewing playing a major impact in observed reduction. In addition, other metabolites including deoxynivalenol-3-glucoside, 15-acetyl-deoxynivalenol, α-zearalenol, and ß-zearalenol which were initially not present in the raw sorghum were detected in the final beer product at the following concentrations 26 ± 11, 16 ± 7.7, 22 ± 18, and 31 ± 16 µg/kg, respectively. HT-2 toxin was also detected at a concentration of 36 ± 13 µg/kg along the processing chain (milled malted fraction) of the traditional beer. For the traditional spices, HT-2 toxin was detected (12 µg/kg) in ogiri. Although there was a reduction of mycotoxins during processing, appreciable concentrations of these toxins were still detected in the final products. Thus, the use of good quality raw materials significantly reduces mycotoxin contamination in final products.

Co-occurrence and distribution of deoxynivalenol, nivalenol and zearalenone in wheat from Brazil.

Fusarium mycotoxins deoxynivalenol (DON), nivalenol (NIV) and zearalenone (ZEN) were investigated in wheat from the 2009 and 2010 crop years. Samples (n = 745) from commercial fields were collected in four wheat producing regions (WPR) which differed in weather conditions. Analyses were performed using HPLC-DAD. Contamination with ZEN, DON and NIV occurred in 56, 86 and 50%, respectively. Also, mean concentrations were different: DON = 1046 µg kg(-1), NIV < 100 µg kg(-1) and ZEN = 82 µg kg(-1). Co-occurrence of ZEN, DON and NIV was observed in 74% of the samples from 2009 and in 12% from 2010. Wet/cold region WPR I had the highest mycotoxin concentration. Wet/moderately hot region WPR II had the lowest mycotoxin levels. Furthermore, the mean concentration of each mycotoxin was higher in samples from 2009 as compared with those from 2010. Precipitation during flowering or harvest periods may explain these results.

Co-occurrence of mycoflora, aflatoxins and fumonisins in maize and rice seeds from markets of different districts in Cairo, Egypt.

The mycoflora and mycotoxins contamination of commercial maize and rice grains collected from local markets of the major five zones of the province of Cairo, Egypt, represented by 20 different districts were studied. A total number of about 23 species belonging to 12 different genera of fungi were isolated and identified. About 70% of the samples were infected with Aspergillus flavus and Aspergillus niger, with percentages of 33%, 40% recovered from maize and 46%, 27% recovered from rice, respectively. The percentages of infection of maize ranged from 16% to 142%. The percentages of infection of rice seeds ranged from 6% to 93%. Total aflatoxins and fumonisins detected in maize averaged 9.75 and 33 µg/kg, respectively. Total aflatoxins and fumonisins detected in rice averaged 5.15 and 1014 µg/kg, respectively.

The impact of the Fusarium mycotoxin deoxynivalenol on the health and performance of broiler chickens.

The aim of the present experiment was to investigate the effects of feeding grains naturally contaminated with Fusarium mycotoxins on morphometric indices of jejunum and to follow the passage of deoxynivalenol (DON) through subsequent segments of the digestive tract of broilers. A total of 45 1-d-old broiler chickens (Ross 308 males) were randomly allotted to three dietary treatments (15 birds/treatment): (1) control diet; (2) diet contaminated with 1 mg DON/kg feed; (3) diet contaminated with 5 mg DON/kg feed for five weeks. None of the zootechnical traits (body weight, body weight gain, feed intake, and feed conversion) responded to increased DON levels in the diet. However, DON at both dietary levels (1 mg and 5 mg DON/kg feed) significantly altered the small intestinal morphology. In the jejunum, the villi were significantly (P < 0.01) shorter in both DON treated groups compared with the controls. Furthermore, the dietary inclusion of DON decreased (P < 0.05) the villus surface area in both DON treated groups. The absolute or relative organ weights (liver, heart, proventriculus, gizzard, small intestine, spleen, pancreas, colon, cecum, bursa of Fabricius and thymus) were not altered (P > 0.05) in broilers fed the diet containing DON compared with controls. DON and de-epoxy-DON (DOM-1) were analyzed in serum, bile, liver, feces and digesta from consecutive segments of the digestive tract (gizzard, cecum, and rectum). Concentrations of DON and its metabolite DOM-1 in serum, bile, and liver were lower than the detection limits of the applied liquid chromatography coupled with mass spectrometry (LC-MS/MS) method. Only about 10 to 12% and 6% of the ingested DON was recovered in gizzard and feces, irrespective of the dietary DON-concentration. However, the DON recovery in the cecum as percentage of DON-intake varied between 18 to 22% and was not influenced by dietary DON-concentration. Interestingly, in the present trial, DOM-1 did not appear in the large intestine and in feces. The results indicate that deepoxydation in the present study hardly occurred in the distal segments of the digestive tract, assuming that the complete de-epoxydation occurs in the proximal small intestine where the majority of the parent toxin is absorbed. In conclusion, diets with DON contamination below levels that induce a negative impact on performance could alter small intestinal morphology in broilers. Additionally, the results confirm that the majority of the ingested DON quickly disappears through the gastrointestinal tract.