Relationship between environmental factors, dry matter loss and mycotoxin levels in stored wheat and maize infected withFusariumspecies

Abstract

This study examined the relationship between storage environmental factors (water activity (a(w)) (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 CO(2) produced under different interacting conditions of a(w) and temperature. DMLs were quantified using the cumulative CO(2) data, and these were shown to increase as temperature and a(w) 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 (0.97a(w)) 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 0.97a(w); however, at intermediate a(w) levels (0.955a(w)), 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 CO(2) production during storage of grains as an indicator of the level of contamination of the grain with mycotoxins.

Alleviation of zearalenone toxicity by modified halloysite nanotubes in the immune response of swine

“…F. graminearum becomes well established on grain at 28°C (Mylona et al 2012). The rate of ZEN production varies depending on the incubation conditions, and the highest production is obtained with cultures transferred to 12°C (Sherwood & Peberdy 1972).…”

Influence of storage environment on maize grain: CO2 production, dry matter losses and aflatoxins contamination

“…According to Seitz et al, (1982), the contribution to DML from fungi increases during storage at a rate dependent on moisture, temperature, amount and type of kernel damage and level of fungal inoculum on the grain. Recent studies have examined the use of CO2 production during storage of maize, wheat and rice as an indicator of the level of AFs, FMs, deoxynivalenol (DON), ZEA and trichothecenes A (TCT-A) contamination (Garcia-Cela, Kiaitsi, Medina, et al, 2018;Martín Castaño, Medina, & Magan, 2017a,b;Mylona & Magan, 2011;Mylona, Sulyok, & Magan, 2012) These studies proved that it is possible to utilise the progressive increase in the respiration rate under increasingly conducive conditions for mould growth due to the oxidation of carbohydrates and hence CO2 production, water vapour and heat during aerobic respiration to calculate quality losses as DML. DML can be quantified based on CO2 production and respiration rates using Gas Chromatography (GC) and these data sets are used as a "storability risk index" to predict overall quality changes in stored grain.…”

“…Seitz et al, (1982) showed that a loss of 0.5% DML in stored maize was enough to downgrade this commodity from food to feed, with associated increased risks of aflatoxin contamination. DML of between 1 and 2% in cereals (rice, wheat, maize) contaminated with Fusarium toxins (FMs, DON and ZEA) resulted in contamination levels which exceeded the EU legislative limits (Garcia-Cela, Kiaitsi, Medina, et al, 2018;Martin Castaño, Medina, & Magan, 2017a,b;Mylona, Sulyok, & Magan, 2012).…”

Appropriateness to set a group health‐based guidance value for fumonisins and their modified forms

“…It was also shown that for F. verticillioides the pattern of FB 1-4 production in maize and the relative amount of FB 1 compared to FB 2 , FB 3 and FB 4 , is related to climatic factors, such as water activity and temperature Mylona et al, 2012). It was also shown that for F. verticillioides the pattern of FB 1-4 production in maize and the relative amount of FB 1 compared to FB 2 , FB 3 and FB 4 , is related to climatic factors, such as water activity and temperature Mylona et al, 2012).…”