Mycotoxin production in wheat grains by different Aspergilli in relation to different relative humidities and storage periods.
Four different Aspergilli (Aspergillus oryzae, A. parasiticus, A. terreus and A. versicolor) were grown on wheat grains underdifferent degrees of relative humidity 14, 50, 74, 80 and 90%. Samples of wheat grains were taken monthly for a period of six months and examined for mycotoxin production. A. oryzae was found to produce aflatoxins B1, B2, zearalenone, DON and T-2 toxins under elevated degrees of humidity and prolonged periods of storage. A. parasiticus produced aflatoxins B1, G1, NIV, DON and T-2 toxins in high concentrations during a period of not more than three months storage at 14% relative humidity; at an increased level of relative humidity of 74% ochratoxin A, zearalenone and sterigmatocystin were also produced at high levels. The isolate was drastic in toxin production. A. terrus produced toxins at 14% relative humidity (aflatoxin G2 and DON) at levels much higher than any other prevalent degrees of humidity. A. versicolor is highly sensitive to relative humidity and grain moisture content It produced aflatoxins B1, G1, NIV and DON at a relative humidity of 50% and another toxins (aflatoxin G2, ochratoxins A, B and zearalenone) at 74%. The microorganism can be considered a trichothecene producer under suitable relative humidity.
Atalla
Mohamed Mabrouk
MM
Chemistry of Natural and Microbial Products Department, National Research Centre, Dokki, Cairo, Egypt. atallam@mailcity.com
Hassanein
Naziha Mohamed
NM
El-Beih
Ahmed Atef
AA
Youssef
Youssef Abdel-ghany
YA
D000348:Aflatoxins / Q000032:analysis / Q000096:biosynthesis*; D001230:Aspergillus / Q000254:growth & development / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D005506:Food Contamination; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology; D006813:Humidity; D009793:Ochratoxins / Q000032:analysis / Q000096:biosynthesis; D013241:Sterigmatocystin / Q000032:analysis / Q000096:biosynthesis; D013696:Temperature; D013997:Time Factors; D014908:Triticum / Q000382:microbiology*; D015025:Zearalenone / Q000032:analysis / Q000096:biosynthesis
D000348:Aflatoxins; D009793:Ochratoxins; D013241:Sterigmatocystin; C025589:ochratoxin A; D015025:Zearalenone