Mycoflora and fumonisin contamination in Brazilian sorghum from sowing to harvest.
BACKGROUND
The aim of this study was to characterise the mycoflora and the presence of fumonisin in sorghum grains, correlating the results with the environment and abiotic factors.


RESULTS
Fifty samples (five collections of ten samples each) of sorghum were analysed. All samples were found to be contaminated with fungi, with higher frequencies of Cladosporium spp. (61.8%) and Helminthosporium spp. (33.4%). Fusarium verticillioides was isolated from 15.1% of the samples, with 38% of them being contaminated with fumonisin B(1) (FB(1)) at levels ranging from 50 to 368.78 ng g(-1). Regarding abiotic factors, temperature, water activity and rainfall showed a positive correlation with the frequency of F. verticillioides and FB(1) production. There was a significant positive correlation between relative air humidity and FB(1) production. The results obtained from sexual crosses between standard F mating tester strains and the isolated strains confirmed that the strains isolated were F. verticillioides.


CONCLUSIONS
It can be concluded that the decrease in F. verticillioides and fumonisin contamination occurred owing to atypical climatic factors during the period of sorghum cultivation, when there was any occurrence of rain and the level of water activity of grains did not reach 0.58.
Alves dos Reis
Tatiana
T
Instituto de Ciências Biomédicas, São Paulo, SP, Brazil.
Zorzete
Patricia
P
Pozzi
Claudia Rodrigues
CR
Nascimento da Silva
Valéria
V
Ortega
Edwin
E
Corrêa
Benedito
B
D000391:Air Microbiology; D001938:Brazil; D002963:Cladosporium / Q000302:isolation & purification; D015169:Colony Count, Microbial; D018556:Crops, Agricultural / Q000737:chemistry* / Q000382:microbiology*; D004271:DNA, Fungal / Q000032:analysis / Q000302:isolation & purification; D005506:Food Contamination / Q000517:prevention & control / Q000706:statistics & numerical data; D005517:Foodborne Diseases / Q000517:prevention & control; D037341:Fumonisins / Q000032:analysis*; D005670:Fusarium / Q000235:genetics / Q000302:isolation & purification; D049770:Genes, Mating Type, Fungal; D006375:Helminthosporium / Q000302:isolation & purification; D003904:Mitosporic Fungi / Q000302:isolation & purification*; D012639:Seeds / Q000737:chemistry / Q000382:microbiology; D012987:Soil / Q000032:analysis; D012988:Soil Microbiology; D045868:Sorghum / Q000737:chemistry* / Q000382:microbiology*; D014867:Water / Q000032:analysis; D014887:Weather
D004271:DNA, Fungal; D037341:Fumonisins; D012987:Soil; D014867:Water; C056933:fumonisin B1