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This study has examined the pattern of mycotoxin contamination of maize destined for animal feed in different global regions over a period of 3 years (2018–2020) with up to 1000+ samples analysed in each year. Overall, >75% of samples in each of the survey years were contaminated with multiple mycotoxins regardless of the global region (Europe, Africa, Asia, South Americas countries). Using LC-MS/MS, it was possible to quantify the relative contamination present in the samples in each year from the different regions of eight different mycotoxins including aflatoxin B1 (AFB1), ochratoxin A (OTA) deoxynivalenol (DON), fumonisin B1 (FB1) and B2, zearalenone (ZEA), T-2 and HT-2 toxins. The trends in mycotoxin contamination showed that there was a consistent contamination with DON in the 3 sampling years in all four regions. Interestingly, AFB1 contamination was prevalent in all regions in 2018, but more predominant in Europe and in 2019. In contrast, in 2020 it was found to be the major contaminant in Africa only. However, FB1 contamination of maize which was prevalent in Europe in 2018, became more prevalent in Asia and LATAM countries in 2019 and even in African maize in 2020. Comparisons of contamination with different mycotoxins in each of the years globally showed significant differences for AFB1, FB1, DON and ZEA between the different years. These results are discussed in relation to the trends of contamination of maize with mixtures of mycotoxins and the implication for their control in this key commodity used as an important ingredient in animal feed. [ABSTRACT FROM AUTHOR]

Heavy metal–contaminated soils are a serious environmental problem. Herein, the culturable heterotrophic bacterial community present on two metal(loid)-contaminated sites in the Northern Portugal was investigated. The bacterial counts ranged from 5.96 to 7.69 and 7.04 to 7.51 (log CFU g−1soil) in Sites 1 and 3, respectively. The bacterial population was predominantly composed ofFirmicutes, Proteobacteria, andActinobacteriaon both sites. The most represented genera in Site 1 wereBacillus(41%) andPseudomonas(27%), whereasArthrobacter(21%) andPseudomonas(13%) were the most represented genera in Site 3. Several bacterial isolates showed tolerance to high concentrations of metal(loid)s, suggesting that both contaminated sites are a valuable source of metal(loid)-tolerant bacteria, which may be further used in bioremediation and/or phytoremediation processes. [ABSTRACT FROM PUBLISHER]

Alternaria species are common saprophytes or pathogens of a wide range of plants pre- and post-harvest. This review considers the relative importance of Alternaria species, their ecology, competitiveness, production of mycotoxins and the prevalence of the predominant mycotoxins in different food products. The available toxicity data on these toxins and the potential future impacts of Alternaria species and their toxicity in food products pre- and post-harvest are discussed. The growth of Alternaria species is influenced by interacting abiotic factors, especially water activity (aw), temperature and pH. The boundary conditions which allow growth and toxin production have been identified in relation to different matrices including cereal grain, sorghum, cottonseed, tomato, and soya beans. The competitiveness of Alternaria species is related to their water stress tolerance, hydrolytic enzyme production and ability to produce mycotoxins. The relationship between A. tenuissima and other phyllosphere fungi has been examined and the relative competitiveness determined using both an Index of Dominance (ID) and the Niche Overlap Index (NOI) based on carbon-utilisation patterns. The toxicology of some of the Alternaria mycotoxins have been studied; however, some data are still lacking. The isolation of Alternaria toxins in different food products including processed products is reviewed. The future implications of Alternaria colonization/infection and the role of their mycotoxins in food production chains pre- and post-harvest are discussed. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effects of calcium propionate, water activity (aw) and incubation time on the total fungal count and aflatoxins B1 (AFB1), B2 (AFB2), G1 (AFG1) and G2 (AFG2) production in the broiler finisher feed. The feed was added with calcium propionate (5 g kg–1), adjusted to 0.85, 0.90 and 0.95 aw and stored for 28 days at 25°C, analysing for mould growth and aflatoxins production every 7 days. Analysis of variance indicated that all the factors (preservative, aw and storage time) alone and in combination significantly (p < 0.001) affected the total fungal count and aflatoxins production in the feed. Minimum total fungal counts (1.99 × 102 CFU g–1) were observed in calcium propionate feed at 0.85 aw on day 1 and the highest (4.36 × 109 CFUs g–1) in control sample at 0.95 aw on day 28 of storage. During the storage period, AFB1 content in control samples increased from 11.35 to 73.44, from 11.58 to 81.81 and from 11.54 to 102.68 ng g–1, whereas in preserved feed the content of B1 increased from 11.47 to 37.83, from 11.54 to 49.07 and from 11.20 to 53.14 ng g–1 at 0.85, 0.90 and 0.95 aw, respectively. Similar patterns were noted for AFB2, AFG1 and AFG2 contents. All the aflatoxins readily increased over storage time; however, the increase was much slower in preserved feed that contained a lower amount of available water. This study reveals that calcium propionate addition to poultry litter along with water activity amelioration is an effective tool for controlling mould incidence and aflatoxin production in poultry feed. [ABSTRACT FROM AUTHOR]

The potential of three atoxigenic strains from different geographical origins in Africa were examined forin vitroandin situcompetitiveness against two toxigenic strains ofAspergillus flavusand subsequent inhibition of aflatoxin B1(AFB1) production under different environmental conditions. Temperature, water activity (aw) and substrate influenced the types of interaction between the three AFL−and two AFL+strains. The competitiveness and AFB1reduction ability of the three atoxigenic strains when interacting with the two toxigenic strains were evaluated by inoculation of 100, 25:75, 50:50, 75:25 and 100% ratios of mixed spore suspensionsin vitroon malt extract and milled maize agars over 28 days andin situon stored maize grain for 14 days, respectively at 0.99, 0.96 and 0.90aw. For all the treatments, the effect ofawand inoculum ratio and their interaction was highly significant. Toxin inhibition was >80%in vitroat both 0.99 and 0.96aw.In situAFB1reduction was influenced by the toxigenic strain assayed,awand the inoculum ratio. Where control was achieved, it was more variable at 0.96aw, while with more stringent water stress conditions (0.90aw) the percentage inhibition was up to 77.2%. The study shows the importance of including environmental factors in screening and identifying effective atoxigenic strains for control of AFs (aflatoxins). [ABSTRACT FROM AUTHOR]

This study examined the relationship between storage environmental factors (water activity (aw) (0.89–0.97) and temperature (15°C–30°C)), colonisation of wheat and maize by Fusarium graminearum and F. verticillioides respectively and the dry matter losses (DMLs) caused and quantified by contamination with deoxynivalenol (DON), zearalenone (ZEA) and fumonisins (FUMs) during storage. Fungal growth was assessed by the amount of CO2 produced under different interacting conditions of aw and temperature. DMLs were quantified using the cumulative CO2 data, and these were shown to increase as temperature and aw increased. The amount of DON, ZEA (wheat for human consumption) and FUMs (feed maize) produced was significantly affected by the storage conditions. The three toxins however showed different patterns of production. Optimum for DON was at the wettest conditions (0.97aw) and the highest temperature assessed (30°C), whereas for ZEA this shifted to 25°C. FUMs were produced in higher amounts in maize at 30°C and 0.97aw; however, at intermediate aw levels (0.955aw), the highest production occurred at 25°C followed by 20°C. Polynomial models were developed for the effect of the storage factors on DMLs and toxin production. DMLs under different environmental conditions were significantly correlated with DON and FUMs. DON contamination was above the EU limits in at least 80% of the wheat samples with DMLs >1%, whereas at least 70% of the same samples contained ZEA above the respective EU legislative limits. Similarly, at least 75% of the maize samples with DMLs ≥ 0.9% exceeded the EU limits for the sum of FUMs in feed. These results show that it may be possible to use temporal CO2 production during storage of grains as an indicator of the level of contamination of the grain with mycotoxins. [ABSTRACT FROM AUTHOR]

A membrane based enzyme linked immunosorbent assay (MELISA) for the detection of a common herbicide, isoproturon is described. A heterogeneous competitive ELISA was the format chosen for isoproturon detection. An immunoassay system with a horseradish peroxidase (HRP) labeled polyclonal antibody preparation was developed and characterized before suitable sensitivity and selectivity for isoproturon were attained. After development as a microtiter plate immunoassay, the system was transferred to an affinity membrane sorbent based ELISA where the isoproturon/ovalbumin conjugate was immobilized on commercial membranes. Different porosities and immobilization conditions were utilized to optimize the MELISA, including sensitivity, selectivity, and stability studies. This enabled detection of isoproturon in the range 0.5 ng ml−1–20 µg ml−1, with an LLD90 of 0.5 ng ml−1. The use of acetonitrile extracts from soil samples was found to not overly impair the performance of the MELISA. Good correlation between ELISA and HPLC was obtained for extracts from spiked soil samples. [ABSTRACT FROM PUBLISHER]

A total of 150 wines, including 123 dry wines (64 red, 49 white and 10 rose) and 27 dessert wines (14 red and 13 white), were obtained from various viticulture and oenological practices across Greece during the period 1999-2006 and analyzed for ochratoxin a (OTA) using immunoaffinity clean-up and HPLC with fluorescence detection. There was a high frequency of OTA in commercially available wines (69% positive samples). However, the level of contamination was relatively low, with only one sample marginally reaching the EU permitted maximum level (2.0 µg l-1). A total of 91% of the samples had OTA concentrations <1.0 µg l-1. The higher concentrations were found in wines from the southern regions, especially in dessert-type wines. There were no significant differences based on wine color or production years. Furthermore, there was no difference between conventional or organic cropping systems in terms of OTA presence. [ABSTRACT FROM AUTHOR]

The quality of harvested wheat grain can deteriorate markedly during the post-harvest management stages. Biotic factors, such as grain type and ripeness, coupled with the prevailing abiotic factors, such as water content and temperature, and also preservative concentration will influence the safe storage life and the level of contamination with mycotoxins. These mycotoxins include deoxynivalenol (DON) produced pre-harvest and zearalenone (ZEA) produced post-harvest by Fusarium graminearum and Fusarium poae, respectively, ochratoxin (OTA) produced by Penicillium verrucosum post-harvest in cool damp northern European climates, and perhaps T-2 and HT-2 toxins produced by Fusarium langsethiae. This review presents recent data on the relationship between dry matter losses caused by F. graminearum under different environmental regimes (water activities, temperatures) and the level of contamination with DON. This is important as poor post-harvest drying and storage management may exacerbate DON contamination already present pre-harvest. It is thus critical to relate the environmental factors in stored wheat grain during storage, especially of intergranular relative humidity (RH) and temperature, to safe storage periods without spoilage or risk from increased DON contamination. The growth/no growth and DON/no DON (F. graminearum) and OTA/no toxin production (P. verrucosum) have been used to build a model with a simple interface to link temperature and RH values to the potential risk level which may allow growth or toxin production. This paper also considers the use of modified atmospheres, preservatives and biocontrol to minimise DON and OTA in moist wheat grain. These approaches together with clear monitoring criteria and hygiene could contribute to better post-harvest management of stored temperate cereals and ensure that mycotoxin contamination is minimised during this key phase in the food/feed chain. [ABSTRACT FROM AUTHOR]

The major hurdle in the production of commercial biocontrol agents (BCAs) has been the lack of production of appropriate formulations. Of particular importance is the conservation of viability and ecological competence after application. With this in mind studies were conducted to develop formulations of P. anomala which would have these attributes. Cells were grown in molasses-based medium modified with proline to different water availability levels (0.98 and 0.96) which significantly increased (up to 50%) the content of trehalose and arabitol in the yeast cells during liquid broth fermentation. The use of isotonic solutions for harvesting the yeast cells further increased the endogenous content of these compatible solutes as well as glycerol. Fluidised bed drying of cells at 30-80°C was carried out for 10 and 20 min and showed that viability was significantly decreased at 70-80°C. A temperature of 50°C for 20 min was found to be best for viability (70%) and moisture content of <10%. Several additives for conservation of viability showed that cotton seed flour+skimmed milk was the best treatment when dried at 50°C. The biocontrol efficacy of formulated P. anomala cells was tested in laboratory scale studies and this showed that they inhibited growth of Penicillium verrucosum and reduce ochratoxin A production in moist wheat grain under some combinations of water availability. Physiologically modified formulated yeast cells with increased levels of trehalose and arabitol gave similar efficacy as fresh cells. This suggests that ecophysiological manipulation of such BCAs can result in improved ecological competence of such formulations and effective biocontrol. [ABSTRACT FROM AUTHOR]

The aim of this study was the production of high numbers of M. anisopliae blastospores with enhanced germination efficiency under conditions of water-stress (ecological fitness). Different nitrogen sources and concentrations were screened for their ability to induce blastospore production while keeping pH and water activity ( a w ) at fixed levels (6.8, and 0.98 a w , respectively). After optimum nitrogen status was determined (cornsteep solid (CS) + yeast extract (YE); or cottonseed flour (CF) + YE), the effect of interaction of nitrogen source, pH (3.5, 5, 6.8, 8, 9 and 10) and solutes for a w adjustment (KCl, NaCl, PEG 200) on blastospore production, endogenous polyol content (glycerol, erythritol, arabitol and mannitol) and total protein, were determined. For both ionic (NaCl, KCl) and non-ionic solutes (PEG 200), optimum blastospore production (between 4×10 7 and 2×10 8 blastospores ml -1 ) and growth occurred in the pH range 6.8–8, with the CF + YE nitrogen profile giving higher yields than CS + YE. Optimum conditions for high erythritol and total protein endogenous concentrations (40.37–73.44 and 14.33–18.90 mg g -1 fresh weight, respectively) occurred between pH 6.8 and 8 by ionic a w modification (KCl, NaCl) and with the CF + YE nitrogen profile. Germination of blastospores produced under these cultural conditions was between 62 and 89% under conditions of water-stress (0.96 a w ). On the other hand, blastospores with lower amounts of erythritol and total protein content had decreased germination (8–67%). These results could have significant implications for developing a liquid fermentation medium for the production of high numbers of fungal propagules with enhanced efficacy under non-optimum environmental conditions. [ABSTRACT FROM AUTHOR]

The major species of fungi responsible for ochratoxin production (OTA) in a range of commodities are Penicillium verrucosum , Aspergillus ochraceus and Aspergillus section Nigri , especially A. carbonarius. P. verrucosum is particularly important in northern Europe where damp cooler conditions occur and where drying regimes need to be efficient and effective for preventing post-harvest contamination with OTA. A. ochraceus can infect cereals including barley, maize, coffee, cocoa and edible nuts. A. carbonarius has been identified as the key species responsible for OTA contamination of grapes, wine and vine fruits. Recent studies have identified the environmental regimes, especially of temperature and humidity, which are conducive to growth and OTA production by these species pre- and post-harvest and during transport. The optimum and marginal interacting conditions for growth and OTA contamination often vary considerably. This has to be borne in mind when effective preventative management strategies are being implemented. Recent studies with cereals have suggested that isolation frequency can be related to OTA contamination of cereals. A logistical model has been developed and identified that 1000&ThickSpace;CFUs&ThickSpace;g -1 grain of P. verrucosum (CFUs) is the threshold limit at which the probability of exceeding the EU legislative limit of 5&ThickSpace;µg&ThickSpace;kg -1 in cereal grain can be predicted under different storage regimes. Controlled atmospheres&ThickSpace;>50% C0 2 is required to effectively prevent OTA accumulation in damp cereals. With regard to grapes, preharvest contamination with A. carbonarius has been shown to be a good indicator for regional risk in southern Europe from OTA contamination. The ecological conditions for optimum growth and OTA production have been shown to differ with the optima being 30–35°C and 15–25°C and 0.98–0.99 and 0.93–0.95 water activity, respectively. Studies on vine fruits (drying currants) suggest that OTA contamination and increase contamination levels occur during this drying process of 7–14 days. This will be influenced by prevailing weather conditions and drying rates. Minimizing OTA contamination in these and other commodities including coffee and cocoa require clear guidelines on safe moisture and temperature regimes pre- and post-harvest for the development of effective management strategies based on ecological criteria. [ABSTRACT FROM AUTHOR]

The effect of propionic acid, its sodium salt or a commercial formulation of propionates (0.03, 0.05 and 0.07%), on growth and fumonisin B1 production by Fusarium verticillioides and F. proliferatum isolates was evaluated on irradiated maize at different water activities (aw, 0.93, 0.95, 0.98) and temperatures (15, 25 C). The four isolates grew at all a temperaw ture treatments in the absence of propionates. At the highest propionate concentration tested (0.07% ), however, growth was restricted to 0.98 aw, for F. prolifer atum isolates but not for those of F. verticillioides. Inhibition of growth was maximum when propionates were added in the acid form. In the presence of low propionate concentrations (0.03% ), growth was sometimes enhanced probably due to assimilation of these compounds by the fungus. W ater activity, temperature, concentration and source of propionate, as well as most two-, three-, four-, and five-way interactions had a significant influence on growth of Fusarium isolates. None of the assayed treatments had any effect on fumonisin B[sub 1] production by F. verticillioides isolates. For F. proliferatum, higher fumonisin B[sub 1] production occurred in the absence of propionates, and in general concentration decreased with increasing doses of preservatives. Single factors (a[sub w], propionate concentrations and temperature) and temperature a[sub w] and propionate concentration temperature interactions had a significant effect on fumonisin production (p < 0 : 01). Moreover, propionate concentration was the single most important factor, besides temperature, which affected fumonisin B1 production. [ABSTRACT FROM AUTHOR]

Examines the influence of reduced water activity on the solute accumulation in Penicillium frequentas. Efficacy of characterized inocula on peaches control; Isolation of P. frequentas from peaches twigs; Use of Agar plugs in inoculating potato dextrose broth flasks.