Barley (Hordeum vulgare L.) is the second winter crop in Argentina. In the national market, grains are mainly destined to produce malt for beer manufacture. Fusarium species are common, causing Fusarium Head Blight (FHB) in barley, which generates yield and quality losses, as well as mycotoxin occurrence. The aims of this study were to determine (a) the incidence of the main species causing FHB in different locations of the barley-growing region of Argentina, (b) their ability to produce mycotoxins, and (c) the levels of deoxynivalenol (DON) and nivalenol (NIV) natural occurrence in grains at the harvest stage. Additionally, a strain of Bacillus velezensis was studied as a biocontrol agent in order to control F. graminearum sensu stricto and mycotoxin accumulation during the malting process, with the final objective being to reduce DON contamination in the beer manufacture chain. Fusarium graminearum ss was the most prevalent species causing FHB, with Fusarium poae being less distributed. Both species produced several mycotoxins, including NX-2 and NX-3, which is the first report of their production by strains isolated from barley in Argentina. Deoxynivalenol contamination was found in 95% of barley grains during the 2016 harvest season (mean: 0.4 mg/kg), while NIV contamination was present in 29% of samples (mean: 0.49 mg/kg). In the 2017 harvest season, 53.6% of grains were contaminated with DON (mean: 0.42 mg/kg), and 21% with NIV (mean: 0.8 mg/kg). Quantification of F. graminearum ss by real-time PCR during the micro-malting process showed that application of the biocontrol agent before the germination stage was the most effective treatment, with a 45% reduction in fungal DNA levels. Reduction in DON contamination (69.3–100%) in artificially infected grains with F. graminearum ss, was also observed. The present work contributes to the knowledge of FHB in Argentina and to the development of a strategy to control this disease and mycotoxin contamination in barley, promoting at the same time food security.

Maize (Zea mays L.) is an important crop in Argentina. Aspergillus section Flavi can infect this crop at the pre-harvest stage, and the harvested grains can be contaminated with aflatoxins (AFs). During the production of bioethanol from maize, AF levels can increase up to three times in the final co-products, known as, dry and wet distiller’s grain with solubles (DDGS and WDGS), intended for animal feed. Fungal enzymes like laccases can be a useful tool for reducing AF contamination in the co-products obtained from this process. The aim of the present study was to evaluate the ability of laccase enzymes included in enzymatic extracts (EE) produced by different species in the Basidiomycota phylum to reduce AF (AFB₁ and AFB₂) accumulation under the conditions of in vitro assays. Four laccase activities (5, 10, 15, and 20 U/mL) exerted by nine isolates were evaluated in the absence and presence of vanillic acid (VA), serving as a laccase redox mediator for the degradation of total AFs. The enzymatic stability in maize steep liquor (MSL) was confirmed after a 60 h incubation period. The most effective EE in terms of reducing AF content in the buffer was selected for an additional assay carried out under the same conditions using maize steep liquor obtained after the saccharification stage during the bioethanol production process. The highest degradation percentages were observed at 20 U/mL of laccase enzymatic activity and 1 mM of VA, corresponding to 26% for AFB₁ and 26.6% for AFB_2. The present study provides valuable data for the development of an efficient tool based on fungal laccases for preventing AF accumulation in the co-products of bioethanol produced from maize used for animal feed.

The presence of Aspergillus section Flavi and aflatoxins (AFs) in nut chains are of great concern due to the toxic effects of AFs on human and animal health as well as the economic losses during commercialisation. Extreme events related to climate change like increased temperature, severe rainfalls and droughts are modulating factors of fungal growth and mycotoxin production. The Expert Working Group (EWG) on nuts that worked under the frame of the Horizon 2020 Mycokey Project prepared this review based on discussions about the situation of contamination with AFs in nuts and the available strategies to reduce the impact of these toxins in the nut chains. The EWG selected as examples peanuts, pistachios and Brazil nuts, and discussed in the review the importance of nut value chains in the production, commercialisation and regulations that establish maximum levels for AFs. Also data on the Rapid Alert System for Food and Feed (RASFF) was considered and showed several notifications for mycotoxins, mainly AFs for nuts and nut products, such as pistachio nuts and dried mix nuts. Under a scenario of climate change, we elaborated strategies to prevent AFs contamination with emphasis on biocontrol and decision support systems. Also, the relevance of strategies to prevent and reduce both fungal infection and AFs accumulation in peanuts, Brazil nuts and pistachio are included as guidelines.

Maize (Zea mays L.) may be infected by Fusarium verticillioides and F. proliferatum, and consequently contaminated with fumonisins (FBs), as well as the co-products of bioethanol intended for animal feed. Laccase enzymes have a wide industrial application such as mycotoxin degradation. The aims were to isolate and identify fungal laccase-producing strains, to evaluate laccase production, to determine the enzymatic stability under fermentation conditions, and to analyse the effectiveness in vitro of enzymatic extracts (EEs) containing laccases in degrading FB₁. Strains belonging to Funalia trogii, Phellinus tuberculosus, Pleurotus ostreatus, Pycnoporus sanguineus and Trametes gallica species showed laccase activity. Different isoforms of laccases were detected depending on the evaluated species. For the FB₁ decontamination assays, four enzymatic activities (5, 10, 15 and 20 U/mL) were tested, in the absence and presence of vanillic acid (VA) and 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) as redox mediators (1 and 10 mM). Trametes gallica B4-IMICO-RC EE was the most effective strain in buffer, achieving a 60% of FB₁ reduction. Laccases included in EEs remained stable at different alcoholic degrees in maize steep liquor (MSL), but no significant FB₁ reduction was observed under the conditions evaluated using MSL. This study demonstrate that although laccases could be good candidates for the development of a strategy to reduce FB₁, further studies are necessary to optimise this process in MSL.

Aflatoxins (AFs) are secondary metabolites produced by Aspergillus section Flavi, mainly Aspergillus flavus and Aspergillus parasiticus. These species may infect food and feed along entire agri-food chains, synthesizing the toxin when environmental conditions are favorable. The scenario of climate change that the world will have to face in the next decades is expected to increase the levels of AF contamination in cereals, nuts, spices, and legumes, among other important crops around the world. This situation will have a great impact on human and animal health, as well as economic losses due to the rejection of contaminated products during commercialization. Several mitigation strategies have been implemented to counteract this problem. Some of them are intended to prevent AF synthesis, while others are designed to decontaminate the pre-formed toxin. In addition, several pre- and post-harvest strategies have shown effectivity. Besides physical and chemical tools, biological control based on different microorganisms and the use of enzymes have been proposed as promissory approaches to mitigate the risk of AF contamination. In this chapter, detailed information about two developments is presented: biocontrol based on prevention by a non-toxigenic A. flavus strain and the use of fungal laccases to decontaminate AFs. The integration of these tools will enhance the quality of food and feed, contributing to food safety in agri-food chains.