Changes in fungi and mycotoxins in pearl millet under controlled storage conditions.
Pearl millet is increasingly being grown as a premium-value grain for the recreational wildlife and poultry industries in the southern US. We conducted three experiments to assess grain mold development in storage conditions typically encountered in the region of production. Variables included production year, temperature, relative humidity, atmosphere, and grain moisture content. In the first experiment, grain was stored for 9 weeks at 20 or 25 degrees C and maintained at 86% or 91% relative humidity (r.h.). In the second experiment, grain was stored for 9 weeks at 20 or 25 degrees C in either air (aerobic) or N2 (anaerobic), and maintained at 100% r.h. In the third experiment, high-moisture grain was stored for 3 weeks at 20 or 25 degrees C and maintained at 100% r.h. Grain was sampled at weekly intervals and plated to determine changes in fungal frequency. Fungi isolated included Fusarium chlamydosporum (19% of grain), Curvularia spp. (14%), F. semitectum (16%), Alternaria spp. (9%), Aspergillus flavus (8%), "Helminthosporium"-type spp. (6%), and F. moniliforme sensu lato (3%). Year of grain production significantly affected isolation frequency of fungi. Isolation frequencies from low-moisture grain were rarely affected by temperature, relative humidity, or atmosphere treatments, but was affected by storage duration for some fungi. Changes in isolation of toxigenic fungi occurred in high-moisture grain. Isolation frequency of F. chlamydosporum increased in grain stored at 86% and 91% r.h. Incidence of A. flavus increased in high-moisture grain treatments, particularly at 25 degrees C. Incidence of deoxynivalenol was not affected by storage treatment. Low concentrations of nivalenol were detected in most grain incubated at 100% r.h. Zearalenone was detected only when grain moisture content was 20-22%. Aflatoxin contamination averaged 174 ng g(-1) over all treatments, and increased up to 798 ng g(-1) in high-moisture grain at stored at 25 degrees C.
Jurjevic
Zeljko
Z
Department of Biological and Agricultural Engineering, University of Georgia, Tifton, GA 31793, USA.
Wilson
Jeffrey P
JP
Wilson
David M
DM
Casper
Howard H
HH
D000332:Aerobiosis; D000348:Aflatoxins / Q000032:analysis; D000693:Anaerobiosis; D001203:Ascomycota / Q000737:chemistry / Q000302:isolation & purification; D001230:Aspergillus / Q000737:chemistry / Q000302:isolation & purification; D005516:Food Microbiology; D005658:Fungi / Q000737:chemistry* / Q000302:isolation & purification*; D005670:Fusarium / Q000737:chemistry / Q000302:isolation & purification; D006813:Humidity; D009183:Mycotoxins / Q000032:analysis*; D031782:Pennisetum / Q000382:microbiology*; D013696:Temperature; D013997:Time Factors; D014255:Trichothecenes / Q000032:analysis; D015025:Zearalenone / Q000032:analysis
D000348:Aflatoxins; D009183:Mycotoxins; D014255:Trichothecenes; D015025:Zearalenone; C038405:nivalenol; C007262:deoxynivalenol
J Assoc Off Anal Chem. 1991 Jan-Feb;74(1):81-8
2026580
Appl Microbiol. 1975 Feb;29(2):224-8
803817
Mycopathologia. 2005 Apr;159(3):401-6
15883726
Appl Environ Microbiol. 1991 Apr;57(4):1223-6
1905519
Mycotoxin Res. 1999 Jun;15(2):67-80
23605184
J AOAC Int. 1994 Mar-Apr;77(2):546-50
8199488
Mycopathologia. 2006 Feb;161(2):101-7
16463093