Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/7/2008
Publication Date: 11/4/2008
Citation: Sugita-Konishi, Y., Sugiyama, K., Siro, S., Toshihiko, S., Maragos, C.M., Tomoyuki, K., Takezawa, Y., Kamata, Y. 2008. Co-Contamination of DON and NIV in Domestic Flour in Japan: Survey, Intake, Reduction and Rapid Assay [abstract]. Toxic Microorganisms Joint Panel. p. 15.
Technical Abstract: Nivalenol (NIV) and Deoxynivalenol (DON) are trichothecene mycotoxins produced by Fusarium spp. that contaminate mainly cereal crops, such as wheat, barley, and maize. These mycotoxins are serious health hazards to humans and domestic animals. In Japan, there have been many reports of DON and NIV co-contamination in domestic wheat and barley. These reports have revealed that the regions suffering from mycotoxin contamination can be roughly divided into two types, those where DON is the main contaminant and those where NIV is most common. The Joint WHO/FAO Expert Committee on Food Additives (JECFA) evaluated the risk of DON and set a PMTDI in 2001. Accordingly, in 2002 MHLW of Japan set the provisional MLs as 1.1 mg/kg for unpolished wheat. However, NIV has not yet been evaluated by JECFA because the health problems caused by NIV are of concern in more limited areas, including Japan. To understand the present situation of co-contamination of DON and NIV, we surveyed DON and NIV levels in domestic flour (n=79) harvested during the Spring of 2006. Based on these data and consumption of flour products, the intake of these toxins in Japan has been estimated. These studies also revealed the reduction of DON and NIV during making of bread from domestic and imported flour in industrial bakeries. Further, we introduced a novel rapid screening assay for DON and NIV using a Surface Plasmon Resonance (SPR) biosensor based upon an antigen-antibody reaction. The results of the survey for domestic flour (n=79), collected in the area where wheat is contaminated with both DON and NIV, showed that the averages of DON and NIV were 64.7 µg/kg (Max. 633.4) and 23.3 µg/kg (Max. 236.1), respectively. Assuming all the wheat products consumed were made from domestic wheat, the NIV intake was estimated, and ranged from 0.28 µg/kg bw/day (>20 years old) to 0.85 µg/kg bw/day (1-6 years old). For reduction during bread making, samples of material flour (n=12) used in the baking industry were collected from flour milling companies or bread bakers located in nine prefectures of Japan. Breads (n=35) produced with the flour were simultaneously obtained from the industrial bread bakers. The percentage reductions of DON and NIV on converting flour into bread using industrial baking equipment were estimated at 67.3 ± 19.4 and 51.2 ± 10.6%, respectively. SPR assay was performed using a Biacore T100 SPR system (GE Healthcare Bio-Science) with immobilization of DON-BSA conjugate on CM5 sensor chips. To assay for NIV the extract after centrifugation was passed through an immunoaffinity column (DONPREP, Rhone) to remove DON in the test solution. Calibration curves of assay inhibition showed a good correlation in the range of 1.0-25ng/ml (NIV) and 0.5-25ng/ml (DON). After each injection, guanidine hydrochloride solution in glycine was injected into the sensor chip to dissociate the antibody from DON-BSA. Results of recovery tests for spiked NIV and DON, were 91.9-103% (NIV) and 93.6-118% (DON). The detection limit of this assay was 100ng/ml (NIV) and 50ng/ml (DON). The data obtained from naturally contaminated wheat corresponded to values obtained using LC/MS. The SPR assay for NIV indicated the possibility that NIV can be analyzed by excluding the influence of DON.