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Introducción: Este artículo tiene como objetivo explorar y describir aspectos personales y profesionales como la construcción de identidad, los retos frecuentes en las aulas de clase en el sector público, y los roles que asumen (y que se le otorga) diariamente a los docentes no hablantes nativos de inglés como lengua extranjera en primaria y secundaria, en un contexto influenciado por las visiones nativistas y colonizadoras del inglés en el sur global. Metodología: Esta investigación es de carácter cualitativo y exploratorio, para la recolección de datos se implementaron entrevistas semiestructuradas, narraciones personales y una sesión de grupo focal. Los informantes de esta investigación fueron cinco profesores de inglés como lengua extranjera de diferentes regiones de Colombia que no se conocen entre ellos y que están vinculados al sector público de la Educación. Resultados: Los resultados revelan que los profesores no hablantes nativos de inglés como lengua extranjera en Colombia usualmente se sienten comparados con los hablantes nativos y relegados en su trabajo. Igualmente, otros asuntos problemáticos como la situación socio-cultural de los estudiantes, y la falta de recursos en las instituciones educativas salen a relucir en este estudio. Conclusión: Los docentes no nativos de inglés en Colombia no son percibidos como el modelo lingüístico a seguir y esto conlleva a desarrollar crisis de identidad profesional al no tener claridad sobre su pertinencia como profesionales en el ámbito de la educación.

The occurrence of fungi and mycotoxins in foods is a serious global problem. Most of the regulated mycotoxins in food are produced by Fusarium spp. This work aimed to assess the antifungal activity of selected lactic acid bacteria (LAB) strains against the main toxigenic Fusarium spp. isolated from cereals. Various machine learning (ML) algorithms such as neural networks (NN), random forest (RF), extreme gradient boosted trees (XGBoost), and multiple linear regression (MLR), were applied to develop models able to predict the percentage of fungal growth inhibition caused by the LAB strains tested. In addition, the ability of the assayed LAB strains to reduce/inhibit the production of the main mycotoxins associated with these fungi was studied by UPLC-MS/MS. All assays were performed at 20, 25, and 30 °C in dual culture (LAB plus fungus) on MRS agar-cereal-based media. All factors and their interactions very significantly influenced the percentage of growth inhibition compared to controls. The efficacy of LAB strains was higher at 20 °C followed by 30 °C and 25 °C. Overall, the order of susceptibility of the fungi to LAB was F. oxysporum F. poae = F. culmorum ≥ F. sporotrichioides F. langsethiae F. graminearum F. subglutinans F. verticillioides. In general, the most effective LAB was Leuconostoc mesenteroides ssp. mesenteroides (T3Y6b), and the least effective were Latilactobacillus sakei ssp. carnosus (T3MM1 and T3Y2). XGBoost and RF were the algorithms that produced the most accurate predicting models of fungal growth inhibition. Mycotoxin levels were usually lower when fungal growth decreased. In the cultures of F. langsethiae treated with LAB, T-2 and HT-2 toxins were not detected except in the treatments with Pediococcus pentosaceus (M9MM5b, S11sMM1, and S1M4). These three strains of P. pentosaceus, L. mesenteroides ssp. mesenteroides (T3Y6b) and L. mesenteroides ssp. dextranicum (T2MM3) inhibited fumonisin production in cultures of F. proliferatum and F. verticillioides. In F. culmorum cultures, zearalenone production was inhibited by all LAB strains, except L. sakei ssp. carnosus (T3MM1) and Companilactobacillus farciminis (T3Y6c), whereas deoxynivalenol and 3-acetyldeoxynivalenol were only detected in cultures of L. sakei ssp. carnosus (T3MM1). The results show that an appropriate selection and use of LAB strains can be one of the most impacting tools in the control of toxigenic Fusarium spp. and their mycotoxins in food and therefore one of the most promising strategies in terms of efficiency, positive impact on the environment, food safety, food security, and international economy.

The efficacy of ethylene-vinyl alcohol copolymer films (EVOH) incorporating the essential oil components cinnamaldehyde (CINHO), citral (CIT), isoeugenol (IEG), or linalool (LIN) to control growth rate (GR) and production of T-2 and HT-2 toxins by Fusarium sporotrichioides cultured on oat grains under different temperature (28, 20, and 15 °C) and water activity (aw) (0.99 and 0.96) regimes was assayed. GR in controls/treatments usually increased with increasing temperature, regardless of aw, but no significant differences concerning aw were found. Toxin production decreased with increasing temperature. The effectiveness of films to control fungal GR and toxin production was as follows: EVOH-CIT &gt, EVOH-CINHO &gt, EVOH-IEG &gt, EVOH-LIN. With few exceptions, effective doses of EVOH-CIT, EVOH-CINHO, and EVOH-IEG films to reduce/inhibit GR by 50%, 90%, and 100% (ED50, ED90, and ED100) ranged from 515 to 3330 µg/culture in Petri dish (25 g oat grains) depending on film type, aw, and temperature. ED90 and ED100 of EVOH-LIN were &gt, 3330 µg/fungal culture. The potential of several machine learning (ML) methods to predict F. sporotrichioides GR and T-2 and HT-2 toxin production under the assayed conditions was comparatively analyzed. XGBoost and random forest attained the best performance, support vector machine and neural network ranked third or fourth depending on the output, while multiple linear regression proved to be the worst.

The potential use of nanotechnology in the control of toxigenic fungi and mycotoxin production has been little explored. In this report, engineered silver nanoparticles (AgNPs) were synthesized and characterized by single particle Inductively Coupled Plasma Mass Spectrometry. Then, their effectiveness in the control of the growth of the main aflatoxigenic and ochratoxigenic species affecting foods and aflatoxins (AFs) and ochratoxin A (OTA) production was studied. The target species and their associated mycotoxins were Aspergillus flavus (AFB1 and AFB2), A. parasiticus (AFB1, AFB2, AFG1 and AFG2), A. carbonarius, A. niger, A. ochraceus, A. steynii, A. westerdijkiae and Penicillium verrucosum (OTA). Spore suspensions supplemented with AgNPs (average diameter size 30 nm, range 14–100 nm) at doses 0–45 μg/mL were incubated for 2–30 h. At selected exposure times aliquots were removed and cultured on maize-based medium (MBM) for 10 days. In these cultures, percentage of viable spores, effective doses (EDs) to inhibit the number of viable spores to 50%, 90% and 100%, colony lag phases, colony growth rates (GR), EDs to inhibit the colony GR to 50%, 90% and 100% were estimated. AF and OTA levels were determined by UPLC-MS/MS. Under the assayed conditions, effective doses of the AgNPs against all the studied fungal species could be estimated. These doses generally decreased with increasing exposure time and were higher for A. flavus and A. parasiticus than for ochratoxigenic species. Colonies from spores treated at high exposure times (20–30 h) and variable AgNP doses showed long lag phases or even did not occur depending on the fungal species. Colony GR, as well as AF and OTA levels in MBM cultures decreased when AgNP dose and contact period increased. The factors species, AgNP dose, exposure time and their interactions significantly affect fungal growth and AF and OTA accumulation in MBM. The results suggest that AgNPs only or as active ingredient hosted in paints, films or other polymers could be a good strategy in the management of the main aflatoxigenic and ocratoxigenic species affecting food and AF and OTA contamination.

Fusarium culmorum and F. proliferatum can grow and produce, respectively, zearalenone (ZEA) and fumonisins (FUM) in different points of the food chain. Application of antifungal chemicals to control these fungi and mycotoxins increases the risk of toxic residues in foods and feeds, and induces fungal resistances. In this study, a new and multidisciplinary approach based on the use of bioactive ethylene-vinyl alcohol copolymer (EVOH) films containing pure components of essential oils (EOCs) and machine learning (ML) methods is evaluated. Bioactive EVOH-EOC films were made incorporating cinnamaldehyde (CINHO), citral (CIT), isoeugenol (IEG) or linalool (LIN). Several ML methods (neural networks, random forests and extreme gradient boosted trees) and multiple linear regression (MLR) were applied and compared for modeling fungal growth and toxin production under different water activity (aw) (0.96 and 0.99) and temperature (20 and 28 °C) regimes. The effective doses to reduce fungal growth rate (GR) by 50, 90 and 100% (ED50, ED90, and ED100) of EOCs in EVOH films were in the ranges 200 to >3330, 450 to >3330, and 660 to >3330 μg/fungal culture (25 g of partly milled maize kernels in Petri dish), respectively, depending on the EOC, aw and temperature. The type of EVOH-EOC film and EOC doses significantly affected GR in both species and ZEA and FUM production. Temperature also affected GR and aw only affected GR and FUM production of F. proliferatum. EVOH-CIT was the most effective film against both species and ZEA and FUM production. Usually, when the EOC levels increased, GR and mycotoxin levels in the medium decreased although some treatments in combination with certain aw and temperature values induced ZEA production. Random forest models predicted the GR of F. culmorum and F. proliferatum and ZEA and FUM production better than neural networks or extreme gradient boosted trees. The MLR mode provided the worst performance. This is the first approach on the ML potential in the study of the impact that bioactive EVOH films containing EOCs and environmental conditions have on F. culmorum and F. proliferatum growth and on ZEA and FUM production. The results suggest that these innovative packaging systems in combination with ML methods can be promising tools in the prediction and control of the risks associated with these toxigenic fungi and mycotoxins in food., Financial support from the European Regional Development Fund (ERDF) and Ministry of Economy and Competitiveness (MINECO, Spanish Government) (Project AGL2014-53928-C2-1-R) and ERDF and Ministry of Science, Innovation and Universities (Spanish Government) (Project RTI2018-097593-B-C22). J.V. Gómez is grateful to MINECO for a PhD contract (Ref. 543071242).

The use of Fusarium-controlling fungicides is necessary to limit crop loss. Little is known about the effect of commercial antifungal formulations at sub-lethal doses, and their interaction with abiotic factors, on Fusarium culmorum and F. proliferatum development and on zearalenone and fumonisin biosynthesis, respectively. In the present study different treatments based on sulfur, trifloxystrobin and demethylation inhibitor fungicides (cyproconazole, tebuconazole and prothioconazole) under different environmental conditions, in Maize Extract Medium (MEM), are assayed in vitro. Then, several machine learning methods (neural networks, random forest and extreme gradient boosted trees) have been applied and compared for the first time for modeling growth rate of F. culmorum and F. proliferatum and zearalenone and fumonisin production, respectively. The most effective antifungal treatment was prothioconazole, 250 g/L + tebuconazole, 150 g/L. Effective doses of this formulation for reduction or total fungal growth inhibition ranged as follows ED50 0.49–1.70, ED90 2.57–6.02 and ED100 4.0–8.0 μg/mL, depending on the species, water activity and temperature. Overall, the growth rate and mycotoxin levels in cultures decreased when doses increased. However, some treatments in combination with certain aw and temperature values significantly induced toxin production. The extreme gradient boosted tree was the machine learning model able to predict growth rate and mycotoxin production with minimum error and maximum R2 value.

Cereal grains are essential ingredient in food, feed and industrial processing. One of the major causes of cereal spoilage and mycotoxin contamination is the presence of toxigenic Fusarium spp. Nanoparticles have immense applications in agriculture, nutrition, medicine or health but their possible impact on the management of toxigenic fungi and mycotoxins have been very little explored. In this report, the potential of silver nanoparticles (AgNPs) (size 14–100 nm) against the major toxigenic Fusarium spp. affecting crops and their effect on mycotoxin accumulation is evaluated for the first time. The studied Fusarium spp. (and associated mycotoxins) were F. graminearum and F. culmorum (deoxynivalenol, 3-acetyldeoxynivalenol and zearalenone), F. sporotrichioides and F. langsethiae (T–2 and HT–2 toxins), F. poae (nivalenol), F. verticillioides and F. proliferatum (fumonisins B1 and B2) and F. oxysporum (mycotoxins no detected). The factors fungal species, AgNP dose (range 2–45 μg/mL), exposure time (range 2–30 h) and their interactions significantly influence spore viability, lag period and growth rate (GR) in subsequent cultures in maize-based medium (MBM) of all the studied species. The effective lethal doses (ED50, ED90 and ED100) to control spore viability and GR were in the range 1–>45 μg/mL depending on the remaining factors. At high exposure times (20−30 h), the three effective doses ranged 1–30 μg/mL for all the studied species. At the end of the incubation period (10 days) mycotoxin levels in MBM cultures inoculated with fungal spores from treatments were strongly related with the size reached by the colony at that time. None of the treatments produced stimulation in conidia germination, GR or mycotoxin biosynthesis with respect to controls. Thus, the antifungal effect of the assayed AgNPs against the tested Fusarium spp. suggests that AgNPs could be a new antifungal ingredient in bioactive polymers (paints, films or coating) likely to be implemented in the agro-food sector for controlling these important toxigenic Fusarium spp. and their main associated mycotoxins.

Mycotoxins are secondary metabolites produced mainly by fungal species belonging to the genera Fusarium, Aspergillus and Penicillium and belong to the most relevant contaminants of food and feed. Cereals are the main source of mycotoxins in the diet. The most prominent mycotoxins are aflatoxins B1, B2, G1 and G2 (AFB1, AFB2, AFG1 and AFG2), fumonisins B1 and B2 (FB1 and FB2), ochratoxin A (OTA), zearalenone (ZEA), deoxynivalenol (DON), 3- and 15-acetyl-deoxynivalenol (3- and 15-ADON), and T-2 and HT-2 toxins. Maximum levels allowed in food are very different depending on mycotoxin and food type, consumer susceptibility and current legislation in each country. Among cereals, maize and its derivatives deserve special attention. The present study was designed to investigate the occurrence of these mycotoxins in Spanish maize kernels collected in different regions for a five-year period (2015–2019) using a multi-mycotoxin UPLC-MS/MS method. Ninety-eight samples of maize kernels collected in 26 Spanish grain stores were ground to fine powder, extracted with acetonitrile-water-formic acid (80:19:1, v/v/v), centrifuged and analyzed by UPLC-ESI-MS/MS using matrix-matched calibration. The method was validated and mean recovery rates were 83–103.4% and mean relative standard deviations ranged from 4.1 to 8.5%. FB1, FB2, DON, 3-ADON, ZEA, AFB1, AFB2, AFG2, T-2 and HT-2 toxins were detected at levels higher than their respective limits of quantification in 71.4%, 56.2%, 31.6%, 5.02%, 24.5%, 9.2%, 9.2%, 2%, 5.1% and 5.1% of maize kernel samples, respectively. OTA was not detected. Among the positive samples, 20.4%, 5.1%, 3%, and 3% had levels exceeding the European Union permissible limits for FB1+FB2, ZEA, AFB1, and total aflatoxins, respectively. Co-occurrence of various mycotoxins (two to seven) in the same sample at quantifiable levels was observed in 33.5% of samples being the association of FB1, FB2 and DON the most frequent, followed by the presence of FB1, FB2, ZEA and DON.

Recent research has showed that Aspergillus flavus and Aspergillus parasiticus are aflatoxigenic species that can become very competitive in the framework of climate change. Aflatoxins show carcinogenic, mutagenic, immunotoxic and teratogenic effects on human and animals. Effective and sustainable measures to inhibit these species and aflatoxins in food are required. Origanum vulgare and Cinnamomum zeylanicum essential oils (EOs) and their major active constituents, carvacrol and cinnamaldehyde, respectively, were assayed for inhibiting these species and aflatoxin production in maize extract medium under different environmental conditions. Doses of 10-1000 mg l

Aspergillus steynii and Aspergillus tubingensis are possibly the main ochratoxin A (OTA) producing species in Aspergillus section Circumdati and section Nigri, respectively. OTA is a potent nephrotoxic, teratogenic, embryotoxic, genotoxic, neurotoxic, carcinogenic and immunosuppressive compound being cereals the first source of OTA in the diet. In this study bioactive ethylene-vinyl alcohol copolymer (EVOH) films containing cinnamaldehyde (CINHO), linalool (LIN), isoeugenol (IEG) or citral (CIT) which are major components of some plant essential oils (EOs) were produced and tested against A. steynii and A. tubingensis growth and OTA production in partly milled maize grains. Due to the favourable safety profile, these bioactive compounds are considered in the category “GRAS”. The study was carried out under different water activity (0.96 and 0.99 aw), and temperature (24 and 32 °C) conditions. ANOVA showed that class of film, fungal species, aw and temperature and their interactions significantly affected growth rates (GR), ED50 and ED90 and the doses for total fungal growth inhibition and OTA production. The most effective EVOH films against both species were those containing CINHO. ED50, ED90 and doses for total growth and OTA inhibition were 165–405, 297–614, 333–666 μg of EVOH-CINHO/plate (25 g of maize grains), respectively, depending on environmental conditions. The least efficient were EVOH-LIN films. ED50, ED90 and doses for total growth and OTA inhibition were 2800–>3330, >3330 and >3330 μg of EVOH-LIN/plate (25 g of maize grains), respectively. The effectiveness of the bioactive films increased with increasing doses. Overall, A. tubingensis was less sensitive to treatments than A. steynii. Depending on the species, aw and temperature affected GR and OTA production in a different way. In A. steynii cultures, optimal growth occurred at 0.96 aw and 32 °C while optimal OTA production happened at 0.99 aw and 32 °C. In A. tubingensis cultures optimal growth happened at 0.99 aw and 32 °C, although the best conditions for OTA production were 0.99 aw and 24 °C. Thus, these species can be very competitive in warm climates and storage conditions. The EVOH-CINHO films followed by EVOH-IEG and EVOH-CIT films, designed in this study and applied in vapour phase, can be potent antifungal agents against A. steynii and A. tubingensis and strong inhibitors of OTA biosynthesis in maize grains at very low doses. This is the first study on the impact that interacting environmental conditions and bioactive films containing individual components of EOs have on the growth of these ochratoxigenic fungi and on OTA production in maize grains.