Preparation of a reference material containing sterigmatocystin.
To assure the homogeneity of a reference material for the mycotoxin sterigmatocystin (STE), a study was first conducted to prepare a reference material of rice containing the colouring Food Red 106. The protocol developed was then used to prepare a reference material of rice containing STE. Initially, a V-shaped mixer was used to mix Food Red 106 and ground brown rice, but the resulting mixture was non-homogeneous. However, when a ShakeMaster was used for the simultaneous grinding and mixing of brown rice with Food Red 106, good homogeneity was obtained. Accordingly, a dried culture of Aspergillus versicolor NRRL5219 and brown rice was ground and mixed with the ShakeMaster. To assess the distribution of the STE an Autoprep MF-A 1000 mini-column was used to isolate the STE, and a 115-120% recovery rate was obtained. Repeatability (variability within a day) and intermediate precision (variability between days) were good. According to the IUPAC/ISO/AOAC International Harmonized Protocol for the Proficiency Testing of Analytical Chemistry Laboratories, a homogeneous candidate reference material was obtained. The particle sizes of ground brown rice, ground brown rice containing Food Red 106, and ground brown rice containing a non-STE producing culture of A. oryzae were analysed and they ranged from 10 to 700 microm.
Tanaka
K
K
Agriculture, Forestry and Fisheries Technical Information Organization, Tokyo, Japan. kjtanaka@mtg.biglobe.ne.jp
Sagou
Y
Y
Nakagawa
H
H
Naito
S
S
Kushiro
M
M
D001230:Aspergillus / Q000378:metabolism; D005504:Food Analysis / Q000592:standards*; D005506:Food Contamination / Q000032:analysis*; D006801:Humans; D009183:Mycotoxins / Q000032:analysis*; D012275:Oryza / Q000737:chemistry; D010316:Particle Size; D012015:Reference Standards; D012235:Rhodamines; D013241:Sterigmatocystin / Q000032:analysis*
D009183:Mycotoxins; D012235:Rhodamines; D013241:Sterigmatocystin; C022027:lissamine rhodamine B