Preparation of an In-House Reference Material Containing Fumonisins in Thai Rice and Matrix Extension of the Analytical Method for Japanese Rice

Abstract

Mycotoxin contamination in rice is less reported, compared to that in wheat or maize, however, some Fusarium fungi occasionally infect rice in the paddy field. Fumonisins are mycotoxins mainly produced by Fusarium verticillioides, which often ruins maize. Rice adherent fungus Gibberella fujikuroi is taxonomically near to F. verticillioides, and there are sporadic reports of fumonisin contamination in rice from Asia, Europe and the United States. Therefore, there exists the potential risk of fumonisin contamination in rice as well as the need for the validated analytical method for fumonisins in rice. Although both natural and spiked reference materials are available for some Fusarium mycotoxins in matrices of wheat and maize, there are no reference materials for Fusarium mycotoxins in rice. In this study, we have developed a method for the preparation of a reference material containing fumonisins in Thai rice. A ShakeMaster grinding machine was used for the preparation of a mixed material of blank Thai rice and F. verticillioides-infected Thai rice. The homogeneity of the mixed material was confirmed by one-way analysis of variance, which led this material to serve as an in-house reference material. Using this reference material, several procedures to extract fumonisins from Thai rice were compared. Accordingly, we proved the applicability of an effective extraction procedure for the determination of fumonisins in Japanese rice.

Surveys of rice sold in Canada for aflatoxins, ochratoxin A and fumonisins

“…Fumonisins B 1 , B 2 and B 3 (FB 1 , FB 2 and FB 3 ) were determined in rice by the method of Oh et al (2009) , with some modifications. A 10 g sample plus 1 g NaCl was submerged in 50 ml water for 30 min ( Kushiro et al 2008 ; Awaludin et al 2009 ) and extraction was completed by blending (Polytron) for 3 min with 50 ml acetonitrile-methanol (1 + 1, v/v). After centrifuging at 2000 rpm for 10 min and filtering (Whatman #1), 40 ml PBS (pH 7) were added to a 10 ml aliquot of extract.…”

Developments in mycotoxin analysis: an update for 2010-2011

“…HorRat values were 0.8 to 1.4. Pre-column derivatisation with OPA was also used in two reports examining extraction and clean-up procedures for isolating fumonisins from masa flour (De Girolamo et al, 2011a) or rice (Awaludin et al, 2009). The first of these examined extraction from yellow, white, and blue masa flours, comparing acidic extraction with the use of EDTA (De Girolamo et al, 2011a).…”

“…In examining masa flour and tortilla chips the authors found combined (FB 1 +FB 2 ) levels of up to 1,800 µg/kg in masa flour and 960 µg/kg in tortilla chips. Awaludin et al (2009) developed an in-house reference material and used it to examine factors affecting the extraction of fumonisins from rice. Several solvent:sample ratios were examined.…”

“…Several solvent:sample ratios were examined. Submerging the rice in water for 30 min, before adding methanol to the extraction increased the levels found (Awaludin et al, 2009). Khayoon et al (2010) examined the use of a silica-based monolithic column (Chromolith® RP-18; Merck, Darmstadt, Germany), which shortened the chromatographic separation times of the fumonisins to about 4 min.…”